diff --git a/.drone.yml b/.drone.yml
index 7a18e0d6..05f06e99 100644
--- a/.drone.yml
+++ b/.drone.yml
@@ -2,57 +2,288 @@
 kind: pipeline
 name: testing
 steps:
+- name: restore-cache
+  image: meltwater/drone-cache
+  pull: always
+  settings:
+    backend: "filesystem"
+    restore: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
+
 - name: test-vet
-  image: golang:1.11 # The lowest golang requirement
+  image: golang:1.15
   environment:
     GO111MODULE: "on"
-    GOPROXY: "https://goproxy.cn"
+    GOPROXY: "https://goproxy.io"
+    CGO_ENABLED: 1
+    GOMODCACHE: '/drone/src/pkg.mod'
+    GOCACHE: '/drone/src/pkg.build'
   commands:
     - make vet
-    - make test
+    - make fmt-check
+  volumes:
+  - name: cache
+    path: /go
   when:
     event:
     - push
     - pull_request
 
-- name: test-sqlite
-  image: golang:1.12
+- name: rebuild-cache
+  image: meltwater/drone-cache
+  pull: true
+  settings:
+    backend: "filesystem"
+    rebuild: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
+
+volumes:
+  - name: cache
+    temp: {}
+
+---
+kind: pipeline
+name: test-sqlite
+depends_on:
+  - testing
+steps:
+- name: restore-cache
+  image: meltwater/drone-cache:dev
+  pull: always
+  settings:
+    backend: "filesystem"
+    restore: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
+
+- name: test-sqlite3
+  image: golang:1.15
   environment:
     GO111MODULE: "on"
-    GOPROXY: "https://goproxy.cn"
+    GOPROXY: "https://goproxy.io"
+    CGO_ENABLED: 1
+    GOMODCACHE: '/drone/src/pkg.mod'
+    GOCACHE: '/drone/src/pkg.build'
+  commands:
+  - make test-sqlite3
+  - TEST_CACHE_ENABLE=true make test-sqlite3
+  - TEST_QUOTE_POLICY=reserved make test-sqlite3
+  volumes:
+  - name: cache
+    path: /go
+
+- name: test-sqlite
+  image: golang:1.15
+  environment:
+    GO111MODULE: "on"
+    GOPROXY: "https://goproxy.io"
+    CGO_ENABLED: 1
+    GOMODCACHE: '/drone/src/pkg.mod'
+    GOCACHE: '/drone/src/pkg.build'
   commands:
   - make test-sqlite
   - TEST_CACHE_ENABLE=true make test-sqlite
   - TEST_QUOTE_POLICY=reserved make test-sqlite
-  when:
-    event:
-    - push
-    - pull_request
+  volumes:
+  - name: cache
+    path: /go
+
+- name: rebuild-cache
+  image: meltwater/drone-cache:dev
+  pull: true
+  settings:
+    backend: "filesystem"
+    rebuild: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
+
+volumes:
+  - name: cache
+    temp: {}
+
+---
+kind: pipeline
+name: test-mysql
+depends_on:
+  - testing
+steps:
+- name: restore-cache
+  image: meltwater/drone-cache
+  pull: always
+  settings:
+    backend: "filesystem"
+    restore: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
 
 - name: test-mysql
-  image: golang:1.12
+  image: golang:1.15
   environment:
     GO111MODULE: "on"
-    GOPROXY: "https://goproxy.cn"
+    GOPROXY: "https://goproxy.io"
+    CGO_ENABLED: 1
+    GOMODCACHE: '/drone/src/pkg.mod'
+    GOCACHE: '/drone/src/pkg.build'
     TEST_MYSQL_HOST: mysql
     TEST_MYSQL_CHARSET: utf8
     TEST_MYSQL_DBNAME: xorm_test
     TEST_MYSQL_USERNAME: root
     TEST_MYSQL_PASSWORD:
   commands:
+  - make test
+  - make test-mysql
+  - TEST_CACHE_ENABLE=true make test-mysql
+  - TEST_QUOTE_POLICY=reserved make test-mysql
+  volumes:
+  - name: cache
+    path: /go
+  
+- name: test-mysql-utf8mb4
+  image: golang:1.15
+  depends_on:
+  - test-mysql
+  environment:
+    GO111MODULE: "on"
+    GOPROXY: "https://goproxy.io"
+    CGO_ENABLED: 1
+    GOMODCACHE: '/drone/src/pkg.mod'
+    GOCACHE: '/drone/src/pkg.build'
+    TEST_MYSQL_HOST: mysql
+    TEST_MYSQL_CHARSET: utf8mb4
+    TEST_MYSQL_DBNAME: xorm_test
+    TEST_MYSQL_USERNAME: root
+    TEST_MYSQL_PASSWORD:
+  commands:
   - make test-mysql
   - TEST_CACHE_ENABLE=true make test-mysql
   - TEST_QUOTE_POLICY=reserved make test-mysql
-  when:
-    event:
-    - push
-    - pull_request
+  volumes:
+  - name: cache
+    path: /go
 
-- name: test-mysql8
-  image: golang:1.12
+- name: test-mymysql
+  pull: default
+  image: golang:1.15
+  depends_on:
+    - test-mysql-utf8mb4
   environment:
     GO111MODULE: "on"
-    GOPROXY: "https://goproxy.cn"
+    GOPROXY: "https://goproxy.io"
+    CGO_ENABLED: 1
+    GOMODCACHE: '/drone/src/pkg.mod'
+    GOCACHE: '/drone/src/pkg.build'
+    TEST_MYSQL_HOST: mysql:3306
+    TEST_MYSQL_DBNAME: xorm_test
+    TEST_MYSQL_USERNAME: root
+    TEST_MYSQL_PASSWORD:
+  commands:
+  - make test-mymysql
+  - TEST_CACHE_ENABLE=true make test-mymysql
+  - TEST_QUOTE_POLICY=reserved make test-mymysql
+  volumes:
+  - name: cache
+    path: /go
+
+- name: rebuild-cache
+  image: meltwater/drone-cache
+  depends_on:
+  - test-mysql
+  - test-mysql-utf8mb4
+  - test-mymysql
+  pull: true
+  settings:
+    backend: "filesystem"
+    rebuild: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
+
+volumes:
+  - name: cache
+    temp: {}
+
+services:
+- name: mysql
+  pull: default
+  image: mysql:5.7
+  environment:
+    MYSQL_ALLOW_EMPTY_PASSWORD: yes
+    MYSQL_DATABASE: xorm_test
+
+---
+kind: pipeline
+name: test-mysql8
+depends_on:
+  - test-mysql
+  - test-sqlite
+steps:
+- name: restore-cache
+  image: meltwater/drone-cache
+  pull: always
+  settings:
+    backend: "filesystem"
+    restore: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
+
+- name: test-mysql8
+  image: golang:1.15
+  environment:
+    GO111MODULE: "on"
+    GOPROXY: "https://goproxy.io"
+    CGO_ENABLED: 1
+    GOMODCACHE: '/drone/src/pkg.mod'
+    GOCACHE: '/drone/src/pkg.build'
     TEST_MYSQL_HOST: mysql8
     TEST_MYSQL_CHARSET: utf8mb4
     TEST_MYSQL_DBNAME: xorm_test
@@ -62,19 +293,71 @@ steps:
   - make test-mysql
   - TEST_CACHE_ENABLE=true make test-mysql
   - TEST_QUOTE_POLICY=reserved make test-mysql
-  when:
-    event:
-    - push
-    - pull_request
+  volumes:
+  - name: cache
+    path: /go
 
-- name: test-mysql-utf8mb4
-  image: golang:1.12
+- name: rebuild-cache
+  image: meltwater/drone-cache:dev
+  pull: true
   depends_on:
-  - test-mysql
+  - test-mysql8
+  settings:
+    backend: "filesystem"
+    rebuild: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
+
+volumes:
+  - name: cache
+    temp: {}
+
+services:
+- name: mysql8
+  pull: default
+  image: mysql:8.0
+  environment:
+    MYSQL_ALLOW_EMPTY_PASSWORD: yes
+    MYSQL_DATABASE: xorm_test
+
+---
+kind: pipeline
+name: test-mariadb
+depends_on:
+  - test-mysql8
+steps:
+- name: restore-cache
+  image: meltwater/drone-cache
+  pull: always
+  settings:
+    backend: "filesystem"
+    restore: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
+
+- name: test-mariadb
+  image: golang:1.15
   environment:
     GO111MODULE: "on"
-    GOPROXY: "https://goproxy.cn"
-    TEST_MYSQL_HOST: mysql
+    GOPROXY: "https://goproxy.io"
+    CGO_ENABLED: 1
+    GOMODCACHE: '/drone/src/pkg.mod'
+    GOCACHE: '/drone/src/pkg.build'
+    TEST_MYSQL_HOST: mariadb
     TEST_MYSQL_CHARSET: utf8mb4
     TEST_MYSQL_DBNAME: xorm_test
     TEST_MYSQL_USERNAME: root
@@ -83,38 +366,71 @@ steps:
   - make test-mysql
   - TEST_CACHE_ENABLE=true make test-mysql
   - TEST_QUOTE_POLICY=reserved make test-mysql
-  when:
-    event:
-    - push
-    - pull_request
+  volumes:
+  - name: cache
+    path: /go
 
-- name: test-mymysql
-  pull: default
-  image: golang:1.12
+- name: rebuild-cache
+  image: meltwater/drone-cache:dev
   depends_on:
-    - test-mysql-utf8mb4
+  - test-mariadb
+  pull: true
+  settings:
+    backend: "filesystem"
+    rebuild: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
+
+volumes:
+  - name: cache
+    temp: {}
+
+services:
+- name: mariadb
+  pull: default
+  image: mariadb:10.4
   environment:
-    GO111MODULE: "on"
-    GOPROXY: "https://goproxy.cn"
-    TEST_MYSQL_HOST: mysql:3306
-    TEST_MYSQL_DBNAME: xorm_test
-    TEST_MYSQL_USERNAME: root
-    TEST_MYSQL_PASSWORD:
-  commands:
-  - make test-mymysql
-  - TEST_CACHE_ENABLE=true make test-mymysql
-  - TEST_QUOTE_POLICY=reserved make test-mymysql
-  when:
-    event:
-    - push
-    - pull_request
+    MYSQL_ALLOW_EMPTY_PASSWORD: yes
+    MYSQL_DATABASE: xorm_test
+
+---
+kind: pipeline
+name: test-postgres
+depends_on:
+  - test-mariadb
+steps:
+- name: restore-cache
+  image: meltwater/drone-cache
+  pull: always
+  settings:
+    backend: "filesystem"
+    restore: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
 
 - name: test-postgres
   pull: default
-  image: golang:1.12
+  image: golang:1.15
   environment:
     GO111MODULE: "on"
-    GOPROXY: "https://goproxy.cn"
+    GOPROXY: "https://goproxy.io"
+    CGO_ENABLED: 1
+    GOMODCACHE: '/drone/src/pkg.mod'
+    GOCACHE: '/drone/src/pkg.build'
     TEST_PGSQL_HOST: pgsql
     TEST_PGSQL_DBNAME: xorm_test
     TEST_PGSQL_USERNAME: postgres
@@ -123,19 +439,21 @@ steps:
   - make test-postgres
   - TEST_CACHE_ENABLE=true make test-postgres
   - TEST_QUOTE_POLICY=reserved make test-postgres
-  when:
-    event:
-    - push
-    - pull_request
+  volumes:
+  - name: cache
+    path: /go
 
 - name: test-postgres-schema
   pull: default
-  image: golang:1.12
+  image: golang:1.15
   depends_on:
   - test-postgres
   environment:
     GO111MODULE: "on"
-    GOPROXY: "https://goproxy.cn"
+    GOPROXY: "https://goproxy.io"
+    CGO_ENABLED: 1
+    GOMODCACHE: '/drone/src/pkg.mod'
+    GOCACHE: '/drone/src/pkg.build'
     TEST_PGSQL_HOST: pgsql
     TEST_PGSQL_SCHEMA: xorm
     TEST_PGSQL_DBNAME: xorm_test
@@ -145,17 +463,72 @@ steps:
   - make test-postgres
   - TEST_CACHE_ENABLE=true make test-postgres
   - TEST_QUOTE_POLICY=reserved make test-postgres
-  when:
-    event:
-    - push
-    - pull_request
+  volumes:
+  - name: cache
+    path: /go
+
+- name: rebuild-cache
+  image: meltwater/drone-cache:dev
+  pull: true
+  depends_on:
+  - test-postgres-schema
+  settings:
+    backend: "filesystem"
+    rebuild: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
+
+volumes:
+  - name: cache
+    temp: {}
+
+services:
+- name: pgsql
+  pull: default
+  image: postgres:9.5
+  environment:
+    POSTGRES_DB: xorm_test
+    POSTGRES_USER: postgres
+    POSTGRES_PASSWORD: postgres
+
+---
+kind: pipeline
+name: test-mssql
+depends_on:
+  - test-postgres
+steps:
+- name: restore-cache
+  image: meltwater/drone-cache
+  pull: always
+  settings:
+    backend: "filesystem"
+    restore: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
 
 - name: test-mssql
   pull: default
-  image: golang:1.12
+  image: golang:1.15
   environment:
     GO111MODULE: "on"
-    GOPROXY: "https://goproxy.cn"
+    GOPROXY: "https://goproxy.io"
+    CGO_ENABLED: 1
+    GOMODCACHE: '/drone/src/pkg.mod'
+    GOCACHE: '/drone/src/pkg.build'
     TEST_MSSQL_HOST: mssql
     TEST_MSSQL_DBNAME: xorm_test
     TEST_MSSQL_USERNAME: sa
@@ -164,17 +537,71 @@ steps:
   - make test-mssql
   - TEST_CACHE_ENABLE=true make test-mssql
   - TEST_QUOTE_POLICY=reserved make test-mssql
-  when:
-    event:
-    - push
-    - pull_request
+  - TEST_MSSQL_DEFAULT_VARCHAR=NVARCHAR TEST_MSSQL_DEFAULT_CHAR=NCHAR make test-mssql
+  volumes:
+  - name: cache
+    path: /go
+
+- name: rebuild-cache
+  image: meltwater/drone-cache:dev
+  pull: true
+  settings:
+    backend: "filesystem"
+    rebuild: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
+
+volumes:
+  - name: cache
+    temp: {}
+
+services:
+- name: mssql
+  pull: default
+  image: microsoft/mssql-server-linux:latest
+  environment:
+    ACCEPT_EULA: Y
+    SA_PASSWORD: yourStrong(!)Password
+    MSSQL_PID: Developer
+
+---
+kind: pipeline
+name: test-tidb
+depends_on:
+  - test-mssql
+steps:
+- name: restore-cache
+  image: meltwater/drone-cache
+  pull: always
+  settings:
+    backend: "filesystem"
+    restore: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
 
 - name: test-tidb
   pull: default
-  image: golang:1.12
+  image: golang:1.15
   environment:
     GO111MODULE: "on"
-    GOPROXY: "https://goproxy.cn"
+    GOPROXY: "https://goproxy.io"
+    CGO_ENABLED: 1
+    GOMODCACHE: '/drone/src/pkg.mod'
+    GOCACHE: '/drone/src/pkg.build'
     TEST_TIDB_HOST: "tidb:4000"
     TEST_TIDB_DBNAME: xorm_test
     TEST_TIDB_USERNAME: root
@@ -183,17 +610,66 @@ steps:
   - make test-tidb
   - TEST_CACHE_ENABLE=true make test-tidb
   - TEST_QUOTE_POLICY=reserved make test-tidb
-  when:
-    event:
-    - push
-    - pull_request
+  volumes:
+  - name: cache
+    path: /go
+
+- name: rebuild-cache
+  image: meltwater/drone-cache:dev
+  pull: true
+  settings:
+    backend: "filesystem"
+    rebuild: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
+
+volumes:
+  - name: cache
+    temp: {}
+
+services:
+- name: tidb
+  pull: default
+  image: pingcap/tidb:v3.0.3
+
+---
+kind: pipeline
+name: test-cockroach
+depends_on:
+  - test-tidb
+steps:
+- name: restore-cache
+  image: meltwater/drone-cache
+  pull: always
+  settings:
+    backend: "filesystem"
+    restore: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
 
 - name: test-cockroach
   pull: default
-  image: golang:1.13
+  image: golang:1.15
   environment:
     GO111MODULE: "on"
-    GOPROXY: "https://goproxy.cn"
+    GOPROXY: "https://goproxy.io"
+    CGO_ENABLED: 1
+    GOMODCACHE: '/drone/src/pkg.mod'
+    GOCACHE: '/drone/src/pkg.build'
     TEST_COCKROACH_HOST: "cockroach:26257"
     TEST_COCKROACH_DBNAME: xorm_test
     TEST_COCKROACH_USERNAME: root
@@ -202,103 +678,62 @@ steps:
   - sleep 10
   - make test-cockroach
   - TEST_CACHE_ENABLE=true make test-cockroach
-  when:
-    event:
-    - push
-    - pull_request
+  volumes:
+  - name: cache
+    path: /go
 
-- name: merge_coverage
-  pull: default
-  image: golang:1.12
-  environment:
-    GO111MODULE: "on"
-    GOPROXY: "https://goproxy.cn"
-  depends_on:
-  - test-vet
-  - test-sqlite
-  - test-mysql
-  - test-mysql8
-  - test-mymysql
-  - test-postgres
-  - test-postgres-schema
-  - test-mssql
-  - test-tidb
-  - test-cockroach
-  commands:
-  - make coverage
-  when:
-    event:
-    - push
-    - pull_request
+- name: rebuild-cache
+  image: meltwater/drone-cache:dev
+  pull: true
+  settings:
+    backend: "filesystem"
+    rebuild: true
+    cache_key: '{{ .Repo.Name }}_{{ checksum "go.mod" }}_{{ checksum "go.sum" }}_{{ arch }}_{{ os }}'
+    archive_format: "gzip"
+    filesystem_cache_root: "/go"
+    mount:
+      - pkg.mod
+      - pkg.build
+  volumes:
+  - name: cache
+    path: /go
+
+volumes:
+  - name: cache
+    temp: {}
 
 services:
-
-- name: mysql
-  pull: default
-  image: mysql:5.7
-  environment:
-    MYSQL_ALLOW_EMPTY_PASSWORD: yes
-    MYSQL_DATABASE: xorm_test
-  when:
-    event:
-    - push
-    - tag
-    - pull_request
-
-- name: mysql8
-  pull: default
-  image: mysql:8.0
-  environment:
-    MYSQL_ALLOW_EMPTY_PASSWORD: yes
-    MYSQL_DATABASE: xorm_test
-  when:
-    event:
-    - push
-    - tag
-    - pull_request
-
-- name: pgsql
-  pull: default
-  image: postgres:9.5
-  environment:
-    POSTGRES_DB: xorm_test
-    POSTGRES_USER: postgres
-    POSTGRES_PASSWORD: postgres
-  when:
-    event:
-    - push
-    - tag
-    - pull_request
-
-- name: mssql
-  pull: default
-  image: microsoft/mssql-server-linux:latest
-  environment:
-    ACCEPT_EULA: Y
-    SA_PASSWORD: yourStrong(!)Password
-    MSSQL_PID: Developer
-  when:
-    event:
-    - push
-    - tag
-    - pull_request
-
-- name: tidb
-  pull: default
-  image: pingcap/tidb:v3.0.3
-  when:
-    event:
-    - push
-    - tag
-    - pull_request
-
 - name: cockroach
   pull: default
   image: cockroachdb/cockroach:v19.2.4
   commands:
   - /cockroach/cockroach start --insecure
+
+---
+kind: pipeline
+name: merge_coverage
+depends_on:
+  - testing
+  - test-sqlite
+  - test-mysql
+  - test-mysql8
+  - test-mariadb
+  - test-postgres
+  - test-mssql
+  - test-tidb
+  - test-cockroach
+steps:
+- name: merge_coverage
+  pull: default
+  image: golang:1.15
+  environment:
+    GO111MODULE: "on"
+    GOPROXY: "https://goproxy.io"
+  commands:
+  - make coverage
   when:
+    branch:
+      - master
     event:
-    - push
-    - tag
-    - pull_request
+      - push
+      - pull_request
diff --git a/.gitignore b/.gitignore
index 617d5da7..a3fbadd4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -36,3 +36,4 @@ test.db.sql
 *coverage.out
 test.db
 integrations/*.sql
+integrations/test_sqlite*
\ No newline at end of file
diff --git a/.revive.toml b/.revive.toml
index 64e223bb..6dec7465 100644
--- a/.revive.toml
+++ b/.revive.toml
@@ -15,6 +15,7 @@ warningCode = 1
 [rule.if-return]
 [rule.increment-decrement]
 [rule.var-naming]
+  arguments = [["ID", "UID", "UUID", "URL", "JSON"], []]
 [rule.var-declaration]
 [rule.package-comments]
 [rule.range]
@@ -22,4 +23,5 @@ warningCode = 1
 [rule.time-naming]
 [rule.unexported-return]
 [rule.indent-error-flow]
-[rule.errorf]
\ No newline at end of file
+[rule.errorf]
+[rule.struct-tag]
\ No newline at end of file
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8cd081e0..13e721ec 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,83 @@
 This changelog goes through all the changes that have been made in each release
 without substantial changes to our git log.
 
+## [1.1.0](https://gitea.com/xorm/xorm/releases/tag/1.1.0) - 2021-05-14
+
+* FEATURES
+  * Unsigned Support for mysql (#1889)
+  * Support modernc.org/sqlite (#1850)
+* TESTING
+  * More tests (#1890)
+* MISC
+  * Byte strings in postgres aren't 0x... (#1906)
+  * Fix another bug with #1872 (#1905)
+  * Fix two issues with dumptables (#1903)
+  * Fix comments (#1896)
+  * Fix comments (#1893)
+  * MariaDB 10.5 adds a suffix on old datatypes (#1885)
+
+## [1.0.7](https://gitea.com/xorm/xorm/pulls?q=&type=all&state=closed&milestone=1336) - 2021-01-21
+
+* BUGFIXES
+  * Fix bug for mssql (#1854)
+* MISC
+  * fix_bugs_for_mssql (#1852)
+
+## [1.0.6](https://gitea.com/xorm/xorm/pulls?q=&type=all&state=closed&milestone=1308) - 2021-01-05
+
+* BUGFIXES
+  * Fix bug when modify column on mssql (#1849)
+  * Fix find and count bug with cols (#1826)
+  * Fix update bug (#1823)
+  * Fix json tag with other type (#1822)
+* ENHANCEMENTS
+  * prevent panic when struct with unexport field (#1839)
+  * Automatically convert datetime to int64 (#1715)
+* MISC
+  * Fix index (#1841)
+  * Performance improvement for columnsbyName (#1788)
+
+## [1.0.5](https://gitea.com/xorm/xorm/pulls?q=&type=all&state=closed&milestone=1299) - 2020-09-08
+
+* BUGFIXES
+  * Fix bug of ToDB when update on a nil pointer (#1786)
+  * Fix warnings with schema Sync2 with default varchar as NVARCHAR (#1783)
+  * Do not ever quote asterisk symbol. Fixes #1780 (#1781)
+  * Fix bug on get columns for postgres (#1779)
+
+## [1.0.4](https://gitea.com/xorm/xorm/pulls?q=&type=all&state=closed&milestone=1286) - 2020-09-02
+
+* FEATURES
+  * Add params for mssql to allow redefine varchar as nvarchar or char as nchar (#1741)
+* BUGFIXES
+  * Fix mysql dialect error from invalid db identifier in orderby clause (#1743) (#1751)
+* ENHANCEMENTS
+  * Support get dataSourceName on ContextHook for  monitor which DB executed SQL (#1740)
+* MISC
+  * Correct default detection in MariaDB >= 10.2.7 (#1778)
+
+## [1.0.3](https://gitea.com/xorm/xorm/pulls?q=&type=all&state=closed&milestone=1281) - 2020-07-10
+
+* BUGFIXES
+  * Fix dump of sqlite (#1639)
+* ENHANCEMENTS
+  * Fix index name parsing in SQLite dialect (#1737)
+  * add hooks for Commit and Rollback (#1733)
+
+## [1.0.2](https://gitea.com/xorm/xorm/pulls?q=&type=all&state=closed&milestone=1261) - 2020-06-16
+
+* FEATURES
+  * Add Hook (#1644)
+* BUGFIXES
+  * Fix bug when ID used but no reference table given (#1709)
+  * Fix find and count bug (#1651)
+* ENHANCEMENTS
+  * chore: improve snakeCasedName performance (#1688)
+  * Fix find with another struct (#1666)
+  * fix GetColumns missing ordinal position (#1660)
+* MISC
+  * chore: improve titleCasedName performance (#1691)
+
 ## [1.0.1](https://gitea.com/xorm/xorm/pulls?q=&type=all&state=closed&milestone=1253) - 2020-03-25
 
 * BUGFIXES
diff --git a/Makefile b/Makefile
index 4cccacd8..bf71b0f4 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,9 @@ GOFMT ?= gofmt -s
 TAGS ?=
 SED_INPLACE := sed -i
 
-GOFILES := $(shell find . -name "*.go" -type f)
+GO_DIRS := caches contexts integrations convert core dialects internal log migrate names schemas tags
+GOFILES := $(wildcard *.go)
+GOFILES += $(shell find $(GO_DIRS) -name "*.go" -type f)
 INTEGRATION_PACKAGES := xorm.io/xorm/integrations
 PACKAGES ?= $(filter-out $(INTEGRATION_PACKAGES),$(shell $(GO) list ./...))
 
@@ -20,6 +22,9 @@ TEST_MSSQL_HOST ?= mssql:1433
 TEST_MSSQL_DBNAME ?= gitea
 TEST_MSSQL_USERNAME ?= sa
 TEST_MSSQL_PASSWORD ?= MwantsaSecurePassword1
+TEST_MSSQL_DEFAULT_VARCHAR ?= varchar
+TEST_MSSQL_DEFAULT_CHAR ?= char
+TEST_MSSQL_DO_NVARCHAR_OVERRIDE_TEST ?= true
 
 TEST_MYSQL_HOST ?= mysql:3306
 TEST_MYSQL_CHARSET ?= utf8
@@ -96,7 +101,8 @@ help:
 	@echo " - test-mysql        run integration tests for mysql"
 	@echo " - test-mssql        run integration tests for mssql"
 	@echo " - test-postgres     run integration tests for postgres"
-	@echo " - test-sqlite       run integration tests for sqlite"
+	@echo " - test-sqlite3      run integration tests for sqlite"
+	@echo " - test-sqlite       run integration tests for pure go sqlite"
 	@echo " - test-tidb         run integration tests for tidb"
 	@echo " - vet               examines Go source code and reports suspicious constructs"
 
@@ -144,12 +150,16 @@ test-cockroach\#%: go-check
 test-mssql: go-check
 	$(GO) test $(INTEGRATION_PACKAGES) -v -race -db=mssql -cache=$(TEST_CACHE_ENABLE) -quote=$(TEST_QUOTE_POLICY) \
 	-conn_str="server=$(TEST_MSSQL_HOST);user id=$(TEST_MSSQL_USERNAME);password=$(TEST_MSSQL_PASSWORD);database=$(TEST_MSSQL_DBNAME)" \
+	-default_varchar=$(TEST_MSSQL_DEFAULT_VARCHAR) -default_char=$(TEST_MSSQL_DEFAULT_CHAR) \
+	-do_nvarchar_override_test=$(TEST_MSSQL_DO_NVARCHAR_OVERRIDE_TEST) \
 	-coverprofile=mssql.$(TEST_QUOTE_POLICY).$(TEST_CACHE_ENABLE).coverage.out -covermode=atomic
 
 .PNONY: test-mssql\#%
 test-mssql\#%: go-check
 	$(GO) test $(INTEGRATION_PACKAGES) -v -race -run $* -db=mssql -cache=$(TEST_CACHE_ENABLE) -quote=$(TEST_QUOTE_POLICY) \
 	-conn_str="server=$(TEST_MSSQL_HOST);user id=$(TEST_MSSQL_USERNAME);password=$(TEST_MSSQL_PASSWORD);database=$(TEST_MSSQL_DBNAME)" \
+	-default_varchar=$(TEST_MSSQL_DEFAULT_VARCHAR) -default_char=$(TEST_MSSQL_DEFAULT_CHAR) \
+	-do_nvarchar_override_test=$(TEST_MSSQL_DO_NVARCHAR_OVERRIDE_TEST) \
 	-coverprofile=mssql.$(TEST_QUOTE_POLICY).$(TEST_CACHE_ENABLE).coverage.out -covermode=atomic
 
 .PNONY: test-mymysql
@@ -188,21 +198,37 @@ test-postgres\#%: go-check
 	-conn_str="postgres://$(TEST_PGSQL_USERNAME):$(TEST_PGSQL_PASSWORD)@$(TEST_PGSQL_HOST)/$(TEST_PGSQL_DBNAME)?sslmode=disable" \
 	-quote=$(TEST_QUOTE_POLICY) -coverprofile=postgres.$(TEST_QUOTE_POLICY).$(TEST_CACHE_ENABLE).coverage.out -covermode=atomic
 
+.PHONY: test-sqlite3
+test-sqlite3: go-check
+	$(GO) test $(INTEGRATION_PACKAGES) -v -race -cache=$(TEST_CACHE_ENABLE) -db=sqlite3 -conn_str="./test.db?cache=shared&mode=rwc" \
+	 -quote=$(TEST_QUOTE_POLICY) -coverprofile=sqlite3.$(TEST_QUOTE_POLICY).$(TEST_CACHE_ENABLE).coverage.out -covermode=atomic
+
+.PHONY: test-sqlite3-schema
+test-sqlite3-schema: go-check
+	$(GO) test $(INTEGRATION_PACKAGES) -v -race -schema=xorm -cache=$(TEST_CACHE_ENABLE) -db=sqlite3 -conn_str="./test.db?cache=shared&mode=rwc" \
+	 -quote=$(TEST_QUOTE_POLICY) -coverprofile=sqlite3.$(TEST_QUOTE_POLICY).$(TEST_CACHE_ENABLE).coverage.out -covermode=atomic
+
+.PHONY: test-sqlite3\#%
+test-sqlite3\#%: go-check
+	$(GO) test $(INTEGRATION_PACKAGES) -v -race -run $* -cache=$(TEST_CACHE_ENABLE) -db=sqlite3 -conn_str="./test.db?cache=shared&mode=rwc" \
+	 -quote=$(TEST_QUOTE_POLICY) -coverprofile=sqlite3.$(TEST_QUOTE_POLICY).$(TEST_CACHE_ENABLE).coverage.out -covermode=atomic
+
 .PHONY: test-sqlite
 test-sqlite: go-check
-	$(GO) test $(INTEGRATION_PACKAGES) -v -race -cache=$(TEST_CACHE_ENABLE) -db=sqlite3 -conn_str="./test.db?cache=shared&mode=rwc" \
+	$(GO) test $(INTEGRATION_PACKAGES) -v -race -cache=$(TEST_CACHE_ENABLE) -db=sqlite -conn_str="./test.db?cache=shared&mode=rwc" \
 	 -quote=$(TEST_QUOTE_POLICY) -coverprofile=sqlite.$(TEST_QUOTE_POLICY).$(TEST_CACHE_ENABLE).coverage.out -covermode=atomic
 
 .PHONY: test-sqlite-schema
 test-sqlite-schema: go-check
-	$(GO) test $(INTEGRATION_PACKAGES) -v -race -schema=xorm -cache=$(TEST_CACHE_ENABLE) -db=sqlite3 -conn_str="./test.db?cache=shared&mode=rwc" \
+	$(GO) test $(INTEGRATION_PACKAGES) -v -race -schema=xorm -cache=$(TEST_CACHE_ENABLE) -db=sqlite -conn_str="./test.db?cache=shared&mode=rwc" \
 	 -quote=$(TEST_QUOTE_POLICY) -coverprofile=sqlite.$(TEST_QUOTE_POLICY).$(TEST_CACHE_ENABLE).coverage.out -covermode=atomic
 
 .PHONY: test-sqlite\#%
 test-sqlite\#%: go-check
-	$(GO) test $(INTEGRATION_PACKAGES) -v -race -run $* -cache=$(TEST_CACHE_ENABLE) -db=sqlite3 -conn_str="./test.db?cache=shared&mode=rwc" \
+	$(GO) test $(INTEGRATION_PACKAGES) -v -race -run $* -cache=$(TEST_CACHE_ENABLE) -db=sqlite -conn_str="./test.db?cache=shared&mode=rwc" \
 	 -quote=$(TEST_QUOTE_POLICY) -coverprofile=sqlite.$(TEST_QUOTE_POLICY).$(TEST_CACHE_ENABLE).coverage.out -covermode=atomic
 
+
 .PNONY: test-tidb
 test-tidb: go-check
 	$(GO) test $(INTEGRATION_PACKAGES) -v -race -db=mysql -cache=$(TEST_CACHE_ENABLE) -ignore_select_update=true \
@@ -217,4 +243,4 @@ test-tidb\#%: go-check
 
 .PHONY: vet
 vet:
-	$(GO) vet $(shell $(GO) list ./...)
\ No newline at end of file
+	$(GO) vet $(shell $(GO) list ./...)
diff --git a/README.md b/README.md
index a15be488..67380839 100644
--- a/README.md
+++ b/README.md
@@ -4,9 +4,7 @@
 
 Xorm is a simple and powerful ORM for Go.
 
-[![Build Status](https://drone.gitea.com/api/badges/xorm/xorm/status.svg)](https://drone.gitea.com/xorm/xorm) [![](http://gocover.io/_badge/xorm.io/xorm)](https://gocover.io/xorm.io/xorm)
-[![](https://goreportcard.com/badge/xorm.io/xorm)](https://goreportcard.com/report/xorm.io/xorm)
-[![Join the chat at https://img.shields.io/discord/323460943201959939.svg](https://img.shields.io/discord/323460943201959939.svg)](https://discord.gg/HuR2CF3)
+[![Build Status](https://drone.gitea.com/api/badges/xorm/xorm/status.svg)](https://drone.gitea.com/xorm/xorm) [![](http://gocover.io/_badge/xorm.io/xorm)](https://gocover.io/xorm.io/xorm) [![](https://goreportcard.com/badge/xorm.io/xorm)](https://goreportcard.com/report/xorm.io/xorm) [![Join the chat at https://img.shields.io/discord/323460943201959939.svg](https://img.shields.io/discord/323460943201959939.svg)](https://discord.gg/HuR2CF3)
 
 ## Notice
 
@@ -315,7 +313,7 @@ err := engine.Where(builder.NotIn("a", 1, 2).And(builder.In("b", "c", "d", "e"))
 // SELECT id, name ... FROM user WHERE a NOT IN (?, ?) AND b IN (?, ?, ?)
 ```
 
-* Multiple operations in one go routine, no transation here but resue session memory
+* Multiple operations in one go routine, no transaction here but resue session memory
 
 ```Go
 session := engine.NewSession()
@@ -338,7 +336,7 @@ if _, err := session.Exec("delete from userinfo where username = ?", user2.Usern
 return nil
 ```
 
-* Transation should be on one go routine. There is transaction and resue session memory
+* Transaction should be on one go routine. There is transaction and resue session memory
 
 ```Go
 session := engine.NewSession()
diff --git a/README_CN.md b/README_CN.md
index f6f88310..80245dd3 100644
--- a/README_CN.md
+++ b/README_CN.md
@@ -4,9 +4,7 @@
 
 xorm 是一个简单而强大的Go语言ORM库. 通过它可以使数据库操作非常简便。
 
-[![Build Status](https://drone.gitea.com/api/badges/xorm/xorm/status.svg)](https://drone.gitea.com/xorm/xorm) [![](http://gocover.io/_badge/xorm.io/xorm)](https://gocover.io/xorm.io/xorm)
-[![](https://goreportcard.com/badge/xorm.io/xorm)](https://goreportcard.com/report/xorm.io/xorm)
-[![Join the chat at https://img.shields.io/discord/323460943201959939.svg](https://img.shields.io/discord/323460943201959939.svg)](https://discord.gg/HuR2CF3)
+[![Build Status](https://drone.gitea.com/api/badges/xorm/xorm/status.svg)](https://drone.gitea.com/xorm/xorm) [![](http://gocover.io/_badge/xorm.io/xorm)](https://gocover.io/xorm.io/xorm) [![](https://goreportcard.com/badge/xorm.io/xorm)](https://goreportcard.com/report/xorm.io/xorm) [![Join the chat at https://img.shields.io/discord/323460943201959939.svg](https://img.shields.io/discord/323460943201959939.svg)](https://discord.gg/HuR2CF3)
 
 ## Notice
 
diff --git a/caches/encode.go b/caches/encode.go
index 4ba39924..95536d7e 100644
--- a/caches/encode.go
+++ b/caches/encode.go
@@ -13,22 +13,26 @@ import (
 	"io"
 )
 
-// md5 hash string
+// Md5 return md5 hash string
 func Md5(str string) string {
 	m := md5.New()
 	io.WriteString(m, str)
 	return fmt.Sprintf("%x", m.Sum(nil))
 }
+
+// Encode Encode data
 func Encode(data interface{}) ([]byte, error) {
 	//return JsonEncode(data)
 	return GobEncode(data)
 }
 
+// Decode decode data
 func Decode(data []byte, to interface{}) error {
 	//return JsonDecode(data, to)
 	return GobDecode(data, to)
 }
 
+// GobEncode encode data with gob
 func GobEncode(data interface{}) ([]byte, error) {
 	var buf bytes.Buffer
 	enc := gob.NewEncoder(&buf)
@@ -39,12 +43,14 @@ func GobEncode(data interface{}) ([]byte, error) {
 	return buf.Bytes(), nil
 }
 
+// GobDecode decode data with gob
 func GobDecode(data []byte, to interface{}) error {
 	buf := bytes.NewBuffer(data)
 	dec := gob.NewDecoder(buf)
 	return dec.Decode(to)
 }
 
+// JsonEncode encode data with json
 func JsonEncode(data interface{}) ([]byte, error) {
 	val, err := json.Marshal(data)
 	if err != nil {
@@ -53,6 +59,7 @@ func JsonEncode(data interface{}) ([]byte, error) {
 	return val, nil
 }
 
+// JsonDecode decode data with json
 func JsonDecode(data []byte, to interface{}) error {
 	return json.Unmarshal(data, to)
 }
diff --git a/caches/leveldb.go b/caches/leveldb.go
index d1a177ad..f2f71d84 100644
--- a/caches/leveldb.go
+++ b/caches/leveldb.go
@@ -19,6 +19,7 @@ type LevelDBStore struct {
 
 var _ CacheStore = &LevelDBStore{}
 
+// NewLevelDBStore creates a leveldb store
 func NewLevelDBStore(dbfile string) (*LevelDBStore, error) {
 	db := &LevelDBStore{}
 	h, err := leveldb.OpenFile(dbfile, nil)
@@ -29,6 +30,7 @@ func NewLevelDBStore(dbfile string) (*LevelDBStore, error) {
 	return db, nil
 }
 
+// Put implements CacheStore
 func (s *LevelDBStore) Put(key string, value interface{}) error {
 	val, err := Encode(value)
 	if err != nil {
@@ -50,6 +52,7 @@ func (s *LevelDBStore) Put(key string, value interface{}) error {
 	return err
 }
 
+// Get implements CacheStore
 func (s *LevelDBStore) Get(key string) (interface{}, error) {
 	data, err := s.store.Get([]byte(key), nil)
 	if err != nil {
@@ -75,6 +78,7 @@ func (s *LevelDBStore) Get(key string) (interface{}, error) {
 	return s.v, err
 }
 
+// Del implements CacheStore
 func (s *LevelDBStore) Del(key string) error {
 	err := s.store.Delete([]byte(key), nil)
 	if err != nil {
@@ -89,6 +93,7 @@ func (s *LevelDBStore) Del(key string) error {
 	return err
 }
 
+// Close implements CacheStore
 func (s *LevelDBStore) Close() {
 	s.store.Close()
 }
diff --git a/caches/manager.go b/caches/manager.go
index 05045210..89a14106 100644
--- a/caches/manager.go
+++ b/caches/manager.go
@@ -6,6 +6,7 @@ package caches
 
 import "sync"
 
+// Manager represents a cache manager
 type Manager struct {
 	cacher             Cacher
 	disableGlobalCache bool
@@ -14,6 +15,7 @@ type Manager struct {
 	cacherLock sync.RWMutex
 }
 
+// NewManager creates a cache manager
 func NewManager() *Manager {
 	return &Manager{
 		cachers: make(map[string]Cacher),
@@ -27,12 +29,14 @@ func (mgr *Manager) SetDisableGlobalCache(disable bool) {
 	}
 }
 
+// SetCacher set cacher of table
 func (mgr *Manager) SetCacher(tableName string, cacher Cacher) {
 	mgr.cacherLock.Lock()
 	mgr.cachers[tableName] = cacher
 	mgr.cacherLock.Unlock()
 }
 
+// GetCacher returns a cache of a table
 func (mgr *Manager) GetCacher(tableName string) Cacher {
 	var cacher Cacher
 	var ok bool
diff --git a/contexts/hook.go b/contexts/hook.go
index 71ad8e87..70f114dd 100644
--- a/contexts/hook.go
+++ b/contexts/hook.go
@@ -31,6 +31,7 @@ func NewContextHook(ctx context.Context, sql string, args []interface{}) *Contex
 	}
 }
 
+// End finish the hook invokation
 func (c *ContextHook) End(ctx context.Context, result sql.Result, err error) {
 	c.Ctx = ctx
 	c.Result = result
@@ -38,19 +39,23 @@ func (c *ContextHook) End(ctx context.Context, result sql.Result, err error) {
 	c.ExecuteTime = time.Now().Sub(c.start)
 }
 
+// Hook represents a hook behaviour
 type Hook interface {
 	BeforeProcess(c *ContextHook) (context.Context, error)
 	AfterProcess(c *ContextHook) error
 }
 
+// Hooks implements Hook interface but contains multiple Hook
 type Hooks struct {
 	hooks []Hook
 }
 
+// AddHook adds a Hook
 func (h *Hooks) AddHook(hooks ...Hook) {
 	h.hooks = append(h.hooks, hooks...)
 }
 
+// BeforeProcess invoked before execute the process
 func (h *Hooks) BeforeProcess(c *ContextHook) (context.Context, error) {
 	ctx := c.Ctx
 	for _, h := range h.hooks {
@@ -63,6 +68,7 @@ func (h *Hooks) BeforeProcess(c *ContextHook) (context.Context, error) {
 	return ctx, nil
 }
 
+// AfterProcess invoked after exetue the process
 func (h *Hooks) AfterProcess(c *ContextHook) error {
 	firstErr := c.Err
 	for _, h := range h.hooks {
diff --git a/core/db.go b/core/db.go
index 50c64c6f..ef5ab227 100644
--- a/core/db.go
+++ b/core/db.go
@@ -23,6 +23,7 @@ var (
 	DefaultCacheSize = 200
 )
 
+// MapToSlice map query and struct as sql and args
 func MapToSlice(query string, mp interface{}) (string, []interface{}, error) {
 	vv := reflect.ValueOf(mp)
 	if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Map {
@@ -44,6 +45,7 @@ func MapToSlice(query string, mp interface{}) (string, []interface{}, error) {
 	return query, args, err
 }
 
+// StructToSlice converts a query and struct as sql and args
 func StructToSlice(query string, st interface{}) (string, []interface{}, error) {
 	vv := reflect.ValueOf(st)
 	if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Struct {
@@ -176,6 +178,7 @@ func (db *DB) QueryMap(query string, mp interface{}) (*Rows, error) {
 	return db.QueryMapContext(context.Background(), query, mp)
 }
 
+// QueryStructContext query rows with struct
 func (db *DB) QueryStructContext(ctx context.Context, query string, st interface{}) (*Rows, error) {
 	query, args, err := StructToSlice(query, st)
 	if err != nil {
@@ -184,10 +187,12 @@ func (db *DB) QueryStructContext(ctx context.Context, query string, st interface
 	return db.QueryContext(ctx, query, args...)
 }
 
+// QueryStruct query rows with struct
 func (db *DB) QueryStruct(query string, st interface{}) (*Rows, error) {
 	return db.QueryStructContext(context.Background(), query, st)
 }
 
+// QueryRowContext query row with args
 func (db *DB) QueryRowContext(ctx context.Context, query string, args ...interface{}) *Row {
 	rows, err := db.QueryContext(ctx, query, args...)
 	if err != nil {
@@ -196,10 +201,12 @@ func (db *DB) QueryRowContext(ctx context.Context, query string, args ...interfa
 	return &Row{rows, nil}
 }
 
+// QueryRow query row with args
 func (db *DB) QueryRow(query string, args ...interface{}) *Row {
 	return db.QueryRowContext(context.Background(), query, args...)
 }
 
+// QueryRowMapContext query row with map
 func (db *DB) QueryRowMapContext(ctx context.Context, query string, mp interface{}) *Row {
 	query, args, err := MapToSlice(query, mp)
 	if err != nil {
@@ -208,10 +215,12 @@ func (db *DB) QueryRowMapContext(ctx context.Context, query string, mp interface
 	return db.QueryRowContext(ctx, query, args...)
 }
 
+// QueryRowMap query row with map
 func (db *DB) QueryRowMap(query string, mp interface{}) *Row {
 	return db.QueryRowMapContext(context.Background(), query, mp)
 }
 
+// QueryRowStructContext query row with struct
 func (db *DB) QueryRowStructContext(ctx context.Context, query string, st interface{}) *Row {
 	query, args, err := StructToSlice(query, st)
 	if err != nil {
@@ -220,6 +229,7 @@ func (db *DB) QueryRowStructContext(ctx context.Context, query string, st interf
 	return db.QueryRowContext(ctx, query, args...)
 }
 
+// QueryRowStruct query row with struct
 func (db *DB) QueryRowStruct(query string, st interface{}) *Row {
 	return db.QueryRowStructContext(context.Background(), query, st)
 }
@@ -239,10 +249,12 @@ func (db *DB) ExecMapContext(ctx context.Context, query string, mp interface{})
 	return db.ExecContext(ctx, query, args...)
 }
 
+// ExecMap exec query with map
 func (db *DB) ExecMap(query string, mp interface{}) (sql.Result, error) {
 	return db.ExecMapContext(context.Background(), query, mp)
 }
 
+// ExecStructContext exec query with map
 func (db *DB) ExecStructContext(ctx context.Context, query string, st interface{}) (sql.Result, error) {
 	query, args, err := StructToSlice(query, st)
 	if err != nil {
@@ -251,6 +263,7 @@ func (db *DB) ExecStructContext(ctx context.Context, query string, st interface{
 	return db.ExecContext(ctx, query, args...)
 }
 
+// ExecContext exec query with args
 func (db *DB) ExecContext(ctx context.Context, query string, args ...interface{}) (sql.Result, error) {
 	hookCtx := contexts.NewContextHook(ctx, query, args)
 	ctx, err := db.beforeProcess(hookCtx)
@@ -265,6 +278,7 @@ func (db *DB) ExecContext(ctx context.Context, query string, args ...interface{}
 	return res, nil
 }
 
+// ExecStruct exec query with struct
 func (db *DB) ExecStruct(query string, st interface{}) (sql.Result, error) {
 	return db.ExecStructContext(context.Background(), query, st)
 }
@@ -288,6 +302,7 @@ func (db *DB) afterProcess(c *contexts.ContextHook) error {
 	return err
 }
 
+// AddHook adds hook
 func (db *DB) AddHook(h ...contexts.Hook) {
 	db.hooks.AddHook(h...)
 }
diff --git a/core/db_test.go b/core/db_test.go
index 777ab0ad..e9c2d82d 100644
--- a/core/db_test.go
+++ b/core/db_test.go
@@ -15,25 +15,26 @@ import (
 
 	_ "github.com/go-sql-driver/mysql"
 	_ "github.com/mattn/go-sqlite3"
+	_ "modernc.org/sqlite"
 )
 
 var (
 	dbtype         = flag.String("dbtype", "sqlite3", "database type")
 	dbConn         = flag.String("dbConn", "./db_test.db", "database connect string")
-	createTableSql string
+	createTableSQL string
 )
 
 func TestMain(m *testing.M) {
 	flag.Parse()
 
 	switch *dbtype {
-	case "sqlite3":
-		createTableSql = "CREATE TABLE IF NOT EXISTS `user` (`id` INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, `name` TEXT NULL, " +
+	case "sqlite3", "sqlite":
+		createTableSQL = "CREATE TABLE IF NOT EXISTS `user` (`id` INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, `name` TEXT NULL, " +
 			"`title` TEXT NULL, `age` FLOAT NULL, `alias` TEXT NULL, `nick_name` TEXT NULL, `created` datetime);"
 	case "mysql":
 		fallthrough
 	default:
-		createTableSql = "CREATE TABLE IF NOT EXISTS `user` (`id` INTEGER PRIMARY KEY AUTO_INCREMENT NOT NULL, `name` TEXT NULL, " +
+		createTableSQL = "CREATE TABLE IF NOT EXISTS `user` (`id` INTEGER PRIMARY KEY AUTO_INCREMENT NOT NULL, `name` TEXT NULL, " +
 			"`title` TEXT NULL, `age` FLOAT NULL, `alias` TEXT NULL, `nick_name` TEXT NULL, `created` datetime);"
 	}
 
@@ -45,8 +46,11 @@ func TestMain(m *testing.M) {
 func testOpen() (*DB, error) {
 	switch *dbtype {
 	case "sqlite3":
-		os.Remove("./test.db")
+		os.Remove("./test_sqlite3.db")
 		return Open("sqlite3", "./test.db")
+	case "sqlite":
+		os.Remove("./test_sqlite.db")
+		return Open("sqlite", "./test.db")
 	case "mysql":
 		return Open("mysql", *dbConn)
 	default:
@@ -62,7 +66,7 @@ func BenchmarkOriQuery(b *testing.B) {
 	}
 	defer db.Close()
 
-	_, err = db.Exec(createTableSql)
+	_, err = db.Exec(createTableSQL)
 	if err != nil {
 		b.Error(err)
 	}
@@ -117,7 +121,7 @@ func BenchmarkStructQuery(b *testing.B) {
 	}
 	defer db.Close()
 
-	_, err = db.Exec(createTableSql)
+	_, err = db.Exec(createTableSQL)
 	if err != nil {
 		b.Error(err)
 	}
@@ -162,7 +166,7 @@ func BenchmarkStruct2Query(b *testing.B) {
 	}
 	defer db.Close()
 
-	_, err = db.Exec(createTableSql)
+	_, err = db.Exec(createTableSQL)
 	if err != nil {
 		b.Error(err)
 	}
@@ -208,7 +212,7 @@ func BenchmarkSliceInterfaceQuery(b *testing.B) {
 	}
 	defer db.Close()
 
-	_, err = db.Exec(createTableSql)
+	_, err = db.Exec(createTableSQL)
 	if err != nil {
 		b.Error(err)
 	}
@@ -266,7 +270,7 @@ func BenchmarkSliceInterfaceQuery(b *testing.B) {
 	}
 	defer db.Close()
 
-	_, err = db.Exec(createTableSql)
+	_, err = db.Exec(createTableSQL)
 	if err != nil {
 		b.Error(err)
 	}
@@ -317,7 +321,7 @@ func BenchmarkSliceStringQuery(b *testing.B) {
 	}
 	defer db.Close()
 
-	_, err = db.Exec(createTableSql)
+	_, err = db.Exec(createTableSQL)
 	if err != nil {
 		b.Error(err)
 	}
@@ -368,7 +372,7 @@ func BenchmarkMapInterfaceQuery(b *testing.B) {
 	}
 	defer db.Close()
 
-	_, err = db.Exec(createTableSql)
+	_, err = db.Exec(createTableSQL)
 	if err != nil {
 		b.Error(err)
 	}
@@ -422,7 +426,7 @@ func BenchmarkMapInterfaceQuery(b *testing.B) {
 	}
 	defer db.Close()
 
-	_, err = db.Exec(createTableSql)
+	_, err = db.Exec(createTableSQL)
 	if err != nil {
 		b.Error(err)
 	}
@@ -469,7 +473,7 @@ func BenchmarkMapStringQuery(b *testing.B) {
 	}
 	defer db.Close()
 
-	_, err = db.Exec(createTableSql)
+	_, err = db.Exec(createTableSQL)
 	if err != nil {
 		b.Error(err)
 	}
@@ -515,7 +519,7 @@ func BenchmarkExec(b *testing.B) {
 	}
 	defer db.Close()
 
-	_, err = db.Exec(createTableSql)
+	_, err = db.Exec(createTableSQL)
 	if err != nil {
 		b.Error(err)
 	}
@@ -540,7 +544,7 @@ func BenchmarkExecMap(b *testing.B) {
 	}
 	defer db.Close()
 
-	_, err = db.Exec(createTableSql)
+	_, err = db.Exec(createTableSQL)
 	if err != nil {
 		b.Error(err)
 	}
@@ -573,7 +577,7 @@ func TestExecMap(t *testing.T) {
 	}
 	defer db.Close()
 
-	_, err = db.Exec(createTableSql)
+	_, err = db.Exec(createTableSQL)
 	if err != nil {
 		t.Error(err)
 	}
@@ -616,7 +620,7 @@ func TestExecStruct(t *testing.T) {
 	}
 	defer db.Close()
 
-	_, err = db.Exec(createTableSql)
+	_, err = db.Exec(createTableSQL)
 	if err != nil {
 		t.Error(err)
 	}
@@ -659,7 +663,7 @@ func BenchmarkExecStruct(b *testing.B) {
 	}
 	defer db.Close()
 
-	_, err = db.Exec(createTableSql)
+	_, err = db.Exec(createTableSQL)
 	if err != nil {
 		b.Error(err)
 	}
diff --git a/core/rows.go b/core/rows.go
index a1e8bfbc..c15a59a3 100644
--- a/core/rows.go
+++ b/core/rows.go
@@ -11,11 +11,13 @@ import (
 	"sync"
 )
 
+// Rows represents rows of table
 type Rows struct {
 	*sql.Rows
 	db *DB
 }
 
+// ToMapString returns all records
 func (rs *Rows) ToMapString() ([]map[string]string, error) {
 	cols, err := rs.Columns()
 	if err != nil {
@@ -34,7 +36,7 @@ func (rs *Rows) ToMapString() ([]map[string]string, error) {
 	return results, nil
 }
 
-// scan data to a struct's pointer according field index
+// ScanStructByIndex scan data to a struct's pointer according field index
 func (rs *Rows) ScanStructByIndex(dest ...interface{}) error {
 	if len(dest) == 0 {
 		return errors.New("at least one struct")
@@ -94,7 +96,7 @@ func fieldByName(v reflect.Value, name string) reflect.Value {
 	return reflect.Zero(t)
 }
 
-// scan data to a struct's pointer according field name
+// ScanStructByName scan data to a struct's pointer according field name
 func (rs *Rows) ScanStructByName(dest interface{}) error {
 	vv := reflect.ValueOf(dest)
 	if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Struct {
@@ -120,7 +122,7 @@ func (rs *Rows) ScanStructByName(dest interface{}) error {
 	return rs.Rows.Scan(newDest...)
 }
 
-// scan data to a slice's pointer, slice's length should equal to columns' number
+// ScanSlice scan data to a slice's pointer, slice's length should equal to columns' number
 func (rs *Rows) ScanSlice(dest interface{}) error {
 	vv := reflect.ValueOf(dest)
 	if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Slice {
@@ -155,7 +157,7 @@ func (rs *Rows) ScanSlice(dest interface{}) error {
 	return nil
 }
 
-// scan data to a map's pointer
+// ScanMap scan data to a map's pointer
 func (rs *Rows) ScanMap(dest interface{}) error {
 	vv := reflect.ValueOf(dest)
 	if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Map {
@@ -187,6 +189,7 @@ func (rs *Rows) ScanMap(dest interface{}) error {
 	return nil
 }
 
+// Row reprents a row of  a tab
 type Row struct {
 	rows *Rows
 	// One of these two will be non-nil:
@@ -205,6 +208,7 @@ func NewRow(rows *Rows, err error) *Row {
 	return &Row{rows, err}
 }
 
+// Columns returns all columns of the row
 func (row *Row) Columns() ([]string, error) {
 	if row.err != nil {
 		return nil, row.err
@@ -212,6 +216,7 @@ func (row *Row) Columns() ([]string, error) {
 	return row.rows.Columns()
 }
 
+// Scan retrieves all row column values
 func (row *Row) Scan(dest ...interface{}) error {
 	if row.err != nil {
 		return row.err
@@ -238,6 +243,7 @@ func (row *Row) Scan(dest ...interface{}) error {
 	return row.rows.Close()
 }
 
+// ScanStructByName retrieves all row column values into a struct
 func (row *Row) ScanStructByName(dest interface{}) error {
 	if row.err != nil {
 		return row.err
@@ -258,6 +264,7 @@ func (row *Row) ScanStructByName(dest interface{}) error {
 	return row.rows.Close()
 }
 
+// ScanStructByIndex retrieves all row column values into a struct
 func (row *Row) ScanStructByIndex(dest interface{}) error {
 	if row.err != nil {
 		return row.err
@@ -278,7 +285,7 @@ func (row *Row) ScanStructByIndex(dest interface{}) error {
 	return row.rows.Close()
 }
 
-// scan data to a slice's pointer, slice's length should equal to columns' number
+// ScanSlice scan data to a slice's pointer, slice's length should equal to columns' number
 func (row *Row) ScanSlice(dest interface{}) error {
 	if row.err != nil {
 		return row.err
@@ -300,7 +307,7 @@ func (row *Row) ScanSlice(dest interface{}) error {
 	return row.rows.Close()
 }
 
-// scan data to a map's pointer
+// ScanMap scan data to a map's pointer
 func (row *Row) ScanMap(dest interface{}) error {
 	if row.err != nil {
 		return row.err
@@ -322,6 +329,7 @@ func (row *Row) ScanMap(dest interface{}) error {
 	return row.rows.Close()
 }
 
+// ToMapString returns all clumns of this record
 func (row *Row) ToMapString() (map[string]string, error) {
 	cols, err := row.Columns()
 	if err != nil {
diff --git a/core/scan.go b/core/scan.go
index 897b5341..1e7e4525 100644
--- a/core/scan.go
+++ b/core/scan.go
@@ -10,12 +10,14 @@ import (
 	"time"
 )
 
+// NullTime defines a customize type NullTime
 type NullTime time.Time
 
 var (
 	_ driver.Valuer = NullTime{}
 )
 
+// Scan implements driver.Valuer
 func (ns *NullTime) Scan(value interface{}) error {
 	if value == nil {
 		return nil
@@ -58,9 +60,11 @@ func convertTime(dest *NullTime, src interface{}) error {
 	return nil
 }
 
+// EmptyScanner represents an empty scanner
 type EmptyScanner struct {
 }
 
+// Scan implements
 func (EmptyScanner) Scan(src interface{}) error {
 	return nil
 }
diff --git a/core/stmt.go b/core/stmt.go
index d46ac9c6..260843d5 100644
--- a/core/stmt.go
+++ b/core/stmt.go
@@ -21,6 +21,7 @@ type Stmt struct {
 	query string
 }
 
+// PrepareContext creates a prepare statement
 func (db *DB) PrepareContext(ctx context.Context, query string) (*Stmt, error) {
 	names := make(map[string]int)
 	var i int
@@ -42,10 +43,12 @@ func (db *DB) PrepareContext(ctx context.Context, query string) (*Stmt, error) {
 	return &Stmt{stmt, db, names, query}, nil
 }
 
+// Prepare creates a prepare statement
 func (db *DB) Prepare(query string) (*Stmt, error) {
 	return db.PrepareContext(context.Background(), query)
 }
 
+// ExecMapContext execute with map
 func (s *Stmt) ExecMapContext(ctx context.Context, mp interface{}) (sql.Result, error) {
 	vv := reflect.ValueOf(mp)
 	if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Map {
@@ -59,10 +62,12 @@ func (s *Stmt) ExecMapContext(ctx context.Context, mp interface{}) (sql.Result,
 	return s.ExecContext(ctx, args...)
 }
 
+// ExecMap executes with map
 func (s *Stmt) ExecMap(mp interface{}) (sql.Result, error) {
 	return s.ExecMapContext(context.Background(), mp)
 }
 
+// ExecStructContext executes with struct
 func (s *Stmt) ExecStructContext(ctx context.Context, st interface{}) (sql.Result, error) {
 	vv := reflect.ValueOf(st)
 	if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Struct {
@@ -76,10 +81,12 @@ func (s *Stmt) ExecStructContext(ctx context.Context, st interface{}) (sql.Resul
 	return s.ExecContext(ctx, args...)
 }
 
+// ExecStruct executes with struct
 func (s *Stmt) ExecStruct(st interface{}) (sql.Result, error) {
 	return s.ExecStructContext(context.Background(), st)
 }
 
+// ExecContext with args
 func (s *Stmt) ExecContext(ctx context.Context, args ...interface{}) (sql.Result, error) {
 	hookCtx := contexts.NewContextHook(ctx, s.query, args)
 	ctx, err := s.db.beforeProcess(hookCtx)
@@ -94,6 +101,7 @@ func (s *Stmt) ExecContext(ctx context.Context, args ...interface{}) (sql.Result
 	return res, nil
 }
 
+// QueryContext query with args
 func (s *Stmt) QueryContext(ctx context.Context, args ...interface{}) (*Rows, error) {
 	hookCtx := contexts.NewContextHook(ctx, s.query, args)
 	ctx, err := s.db.beforeProcess(hookCtx)
@@ -108,10 +116,12 @@ func (s *Stmt) QueryContext(ctx context.Context, args ...interface{}) (*Rows, er
 	return &Rows{rows, s.db}, nil
 }
 
+// Query query with args
 func (s *Stmt) Query(args ...interface{}) (*Rows, error) {
 	return s.QueryContext(context.Background(), args...)
 }
 
+// QueryMapContext query with map
 func (s *Stmt) QueryMapContext(ctx context.Context, mp interface{}) (*Rows, error) {
 	vv := reflect.ValueOf(mp)
 	if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Map {
@@ -126,10 +136,12 @@ func (s *Stmt) QueryMapContext(ctx context.Context, mp interface{}) (*Rows, erro
 	return s.QueryContext(ctx, args...)
 }
 
+// QueryMap query with map
 func (s *Stmt) QueryMap(mp interface{}) (*Rows, error) {
 	return s.QueryMapContext(context.Background(), mp)
 }
 
+// QueryStructContext query with struct
 func (s *Stmt) QueryStructContext(ctx context.Context, st interface{}) (*Rows, error) {
 	vv := reflect.ValueOf(st)
 	if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Struct {
@@ -144,19 +156,23 @@ func (s *Stmt) QueryStructContext(ctx context.Context, st interface{}) (*Rows, e
 	return s.QueryContext(ctx, args...)
 }
 
+// QueryStruct query with struct
 func (s *Stmt) QueryStruct(st interface{}) (*Rows, error) {
 	return s.QueryStructContext(context.Background(), st)
 }
 
+// QueryRowContext query row with args
 func (s *Stmt) QueryRowContext(ctx context.Context, args ...interface{}) *Row {
 	rows, err := s.QueryContext(ctx, args...)
 	return &Row{rows, err}
 }
 
+// QueryRow query row with args
 func (s *Stmt) QueryRow(args ...interface{}) *Row {
 	return s.QueryRowContext(context.Background(), args...)
 }
 
+// QueryRowMapContext query row with map
 func (s *Stmt) QueryRowMapContext(ctx context.Context, mp interface{}) *Row {
 	vv := reflect.ValueOf(mp)
 	if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Map {
@@ -171,10 +187,12 @@ func (s *Stmt) QueryRowMapContext(ctx context.Context, mp interface{}) *Row {
 	return s.QueryRowContext(ctx, args...)
 }
 
+// QueryRowMap query row with map
 func (s *Stmt) QueryRowMap(mp interface{}) *Row {
 	return s.QueryRowMapContext(context.Background(), mp)
 }
 
+// QueryRowStructContext query row with struct
 func (s *Stmt) QueryRowStructContext(ctx context.Context, st interface{}) *Row {
 	vv := reflect.ValueOf(st)
 	if vv.Kind() != reflect.Ptr || vv.Elem().Kind() != reflect.Struct {
@@ -189,6 +207,7 @@ func (s *Stmt) QueryRowStructContext(ctx context.Context, st interface{}) *Row {
 	return s.QueryRowContext(ctx, args...)
 }
 
+// QueryRowStruct query row with struct
 func (s *Stmt) QueryRowStruct(st interface{}) *Row {
 	return s.QueryRowStructContext(context.Background(), st)
 }
diff --git a/core/tx.go b/core/tx.go
index 9b2988af..a2f745f8 100644
--- a/core/tx.go
+++ b/core/tx.go
@@ -18,9 +18,11 @@ var (
 // Tx represents a transaction
 type Tx struct {
 	*sql.Tx
-	db *DB
+	db  *DB
+	ctx context.Context
 }
 
+// BeginTx begin a transaction with option
 func (db *DB) BeginTx(ctx context.Context, opts *sql.TxOptions) (*Tx, error) {
 	hookCtx := contexts.NewContextHook(ctx, "BEGIN TRANSACTION", nil)
 	ctx, err := db.beforeProcess(hookCtx)
@@ -32,13 +34,39 @@ func (db *DB) BeginTx(ctx context.Context, opts *sql.TxOptions) (*Tx, error) {
 	if err := db.afterProcess(hookCtx); err != nil {
 		return nil, err
 	}
-	return &Tx{tx, db}, nil
+	return &Tx{tx, db, ctx}, nil
 }
 
+// Begin begins a transaction
 func (db *DB) Begin() (*Tx, error) {
 	return db.BeginTx(context.Background(), nil)
 }
 
+// Commit submit the transaction
+func (tx *Tx) Commit() error {
+	hookCtx := contexts.NewContextHook(tx.ctx, "COMMIT", nil)
+	ctx, err := tx.db.beforeProcess(hookCtx)
+	if err != nil {
+		return err
+	}
+	err = tx.Tx.Commit()
+	hookCtx.End(ctx, nil, err)
+	return tx.db.afterProcess(hookCtx)
+}
+
+// Rollback rollback the transaction
+func (tx *Tx) Rollback() error {
+	hookCtx := contexts.NewContextHook(tx.ctx, "ROLLBACK", nil)
+	ctx, err := tx.db.beforeProcess(hookCtx)
+	if err != nil {
+		return err
+	}
+	err = tx.Tx.Rollback()
+	hookCtx.End(ctx, nil, err)
+	return tx.db.afterProcess(hookCtx)
+}
+
+// PrepareContext prepare the query
 func (tx *Tx) PrepareContext(ctx context.Context, query string) (*Stmt, error) {
 	names := make(map[string]int)
 	var i int
@@ -60,19 +88,23 @@ func (tx *Tx) PrepareContext(ctx context.Context, query string) (*Stmt, error) {
 	return &Stmt{stmt, tx.db, names, query}, nil
 }
 
+// Prepare prepare the query
 func (tx *Tx) Prepare(query string) (*Stmt, error) {
 	return tx.PrepareContext(context.Background(), query)
 }
 
+// StmtContext creates Stmt with context
 func (tx *Tx) StmtContext(ctx context.Context, stmt *Stmt) *Stmt {
 	stmt.Stmt = tx.Tx.StmtContext(ctx, stmt.Stmt)
 	return stmt
 }
 
+// Stmt creates Stmt
 func (tx *Tx) Stmt(stmt *Stmt) *Stmt {
 	return tx.StmtContext(context.Background(), stmt)
 }
 
+// ExecMapContext executes query with args in a map
 func (tx *Tx) ExecMapContext(ctx context.Context, query string, mp interface{}) (sql.Result, error) {
 	query, args, err := MapToSlice(query, mp)
 	if err != nil {
@@ -81,10 +113,12 @@ func (tx *Tx) ExecMapContext(ctx context.Context, query string, mp interface{})
 	return tx.ExecContext(ctx, query, args...)
 }
 
+// ExecMap executes query with args in a map
 func (tx *Tx) ExecMap(query string, mp interface{}) (sql.Result, error) {
 	return tx.ExecMapContext(context.Background(), query, mp)
 }
 
+// ExecStructContext executes query with args in a struct
 func (tx *Tx) ExecStructContext(ctx context.Context, query string, st interface{}) (sql.Result, error) {
 	query, args, err := StructToSlice(query, st)
 	if err != nil {
@@ -93,6 +127,7 @@ func (tx *Tx) ExecStructContext(ctx context.Context, query string, st interface{
 	return tx.ExecContext(ctx, query, args...)
 }
 
+// ExecContext executes a query with args
 func (tx *Tx) ExecContext(ctx context.Context, query string, args ...interface{}) (sql.Result, error) {
 	hookCtx := contexts.NewContextHook(ctx, query, args)
 	ctx, err := tx.db.beforeProcess(hookCtx)
@@ -107,10 +142,12 @@ func (tx *Tx) ExecContext(ctx context.Context, query string, args ...interface{}
 	return res, err
 }
 
+// ExecStruct executes query with args in a struct
 func (tx *Tx) ExecStruct(query string, st interface{}) (sql.Result, error) {
 	return tx.ExecStructContext(context.Background(), query, st)
 }
 
+// QueryContext query with args
 func (tx *Tx) QueryContext(ctx context.Context, query string, args ...interface{}) (*Rows, error) {
 	hookCtx := contexts.NewContextHook(ctx, query, args)
 	ctx, err := tx.db.beforeProcess(hookCtx)
@@ -128,10 +165,12 @@ func (tx *Tx) QueryContext(ctx context.Context, query string, args ...interface{
 	return &Rows{rows, tx.db}, nil
 }
 
+// Query query with args
 func (tx *Tx) Query(query string, args ...interface{}) (*Rows, error) {
 	return tx.QueryContext(context.Background(), query, args...)
 }
 
+// QueryMapContext query with args in a map
 func (tx *Tx) QueryMapContext(ctx context.Context, query string, mp interface{}) (*Rows, error) {
 	query, args, err := MapToSlice(query, mp)
 	if err != nil {
@@ -140,10 +179,12 @@ func (tx *Tx) QueryMapContext(ctx context.Context, query string, mp interface{})
 	return tx.QueryContext(ctx, query, args...)
 }
 
+// QueryMap query with args in a map
 func (tx *Tx) QueryMap(query string, mp interface{}) (*Rows, error) {
 	return tx.QueryMapContext(context.Background(), query, mp)
 }
 
+// QueryStructContext query with args in struct
 func (tx *Tx) QueryStructContext(ctx context.Context, query string, st interface{}) (*Rows, error) {
 	query, args, err := StructToSlice(query, st)
 	if err != nil {
@@ -152,19 +193,23 @@ func (tx *Tx) QueryStructContext(ctx context.Context, query string, st interface
 	return tx.QueryContext(ctx, query, args...)
 }
 
+// QueryStruct query with args in struct
 func (tx *Tx) QueryStruct(query string, st interface{}) (*Rows, error) {
 	return tx.QueryStructContext(context.Background(), query, st)
 }
 
+// QueryRowContext query one row with args
 func (tx *Tx) QueryRowContext(ctx context.Context, query string, args ...interface{}) *Row {
 	rows, err := tx.QueryContext(ctx, query, args...)
 	return &Row{rows, err}
 }
 
+// QueryRow query one row with args
 func (tx *Tx) QueryRow(query string, args ...interface{}) *Row {
 	return tx.QueryRowContext(context.Background(), query, args...)
 }
 
+// QueryRowMapContext query one row with args in a map
 func (tx *Tx) QueryRowMapContext(ctx context.Context, query string, mp interface{}) *Row {
 	query, args, err := MapToSlice(query, mp)
 	if err != nil {
@@ -173,10 +218,12 @@ func (tx *Tx) QueryRowMapContext(ctx context.Context, query string, mp interface
 	return tx.QueryRowContext(ctx, query, args...)
 }
 
+// QueryRowMap query one row with args in a map
 func (tx *Tx) QueryRowMap(query string, mp interface{}) *Row {
 	return tx.QueryRowMapContext(context.Background(), query, mp)
 }
 
+// QueryRowStructContext query one row with args in struct
 func (tx *Tx) QueryRowStructContext(ctx context.Context, query string, st interface{}) *Row {
 	query, args, err := StructToSlice(query, st)
 	if err != nil {
@@ -185,6 +232,7 @@ func (tx *Tx) QueryRowStructContext(ctx context.Context, query string, st interf
 	return tx.QueryRowContext(ctx, query, args...)
 }
 
+// QueryRowStruct query one row with args in struct
 func (tx *Tx) QueryRowStruct(query string, st interface{}) *Row {
 	return tx.QueryRowStructContext(context.Background(), query, st)
 }
diff --git a/dialects/dialect.go b/dialects/dialect.go
index dc96f73a..b02ec4ae 100644
--- a/dialects/dialect.go
+++ b/dialects/dialect.go
@@ -79,32 +79,34 @@ type Base struct {
 	quoter  schemas.Quoter
 }
 
-func (b *Base) Quoter() schemas.Quoter {
-	return b.quoter
+// Quoter returns the current database Quoter
+func (db *Base) Quoter() schemas.Quoter {
+	return db.quoter
 }
 
-func (b *Base) Init(dialect Dialect, uri *URI) error {
-	b.dialect, b.uri = dialect, uri
+// Init initialize the dialect
+func (db *Base) Init(dialect Dialect, uri *URI) error {
+	db.dialect, db.uri = dialect, uri
 	return nil
 }
 
-func (b *Base) URI() *URI {
-	return b.uri
+// URI returns the uri of database
+func (db *Base) URI() *URI {
+	return db.uri
 }
 
-func (b *Base) DBType() schemas.DBType {
-	return b.uri.DBType
-}
-
-func (b *Base) FormatBytes(bs []byte) string {
+// FormatBytes formats bytes
+func (db *Base) FormatBytes(bs []byte) string {
 	return fmt.Sprintf("0x%x", bs)
 }
 
+// DropTableSQL returns drop table SQL
 func (db *Base) DropTableSQL(tableName string) (string, bool) {
 	quote := db.dialect.Quoter().Quote
 	return fmt.Sprintf("DROP TABLE IF EXISTS %s", quote(tableName)), true
 }
 
+// HasRecords returns true if the SQL has records returned
 func (db *Base) HasRecords(queryer core.Queryer, ctx context.Context, query string, args ...interface{}) (bool, error) {
 	rows, err := queryer.QueryContext(ctx, query, args...)
 	if err != nil {
@@ -118,6 +120,7 @@ func (db *Base) HasRecords(queryer core.Queryer, ctx context.Context, query stri
 	return false, nil
 }
 
+// IsColumnExist returns true if the column of the table exist
 func (db *Base) IsColumnExist(queryer core.Queryer, ctx context.Context, tableName, colName string) (bool, error) {
 	quote := db.dialect.Quoter().Quote
 	query := fmt.Sprintf(
@@ -132,11 +135,13 @@ func (db *Base) IsColumnExist(queryer core.Queryer, ctx context.Context, tableNa
 	return db.HasRecords(queryer, ctx, query, db.uri.DBName, tableName, colName)
 }
 
+// AddColumnSQL returns a SQL to add a column
 func (db *Base) AddColumnSQL(tableName string, col *schemas.Column) string {
 	s, _ := ColumnString(db.dialect, col, true)
 	return fmt.Sprintf("ALTER TABLE %v ADD %v", db.dialect.Quoter().Quote(tableName), s)
 }
 
+// CreateIndexSQL returns a SQL to create index
 func (db *Base) CreateIndexSQL(tableName string, index *schemas.Index) string {
 	quoter := db.dialect.Quoter()
 	var unique string
@@ -150,6 +155,7 @@ func (db *Base) CreateIndexSQL(tableName string, index *schemas.Index) string {
 		quoter.Join(index.Cols, ","))
 }
 
+// DropIndexSQL returns a SQL to drop index
 func (db *Base) DropIndexSQL(tableName string, index *schemas.Index) string {
 	quote := db.dialect.Quoter().Quote
 	var name string
@@ -161,16 +167,19 @@ func (db *Base) DropIndexSQL(tableName string, index *schemas.Index) string {
 	return fmt.Sprintf("DROP INDEX %v ON %s", quote(name), quote(tableName))
 }
 
+// ModifyColumnSQL returns a SQL to modify SQL
 func (db *Base) ModifyColumnSQL(tableName string, col *schemas.Column) string {
 	s, _ := ColumnString(db.dialect, col, false)
-	return fmt.Sprintf("alter table %s MODIFY COLUMN %s", tableName, s)
+	return fmt.Sprintf("ALTER TABLE %s MODIFY COLUMN %s", tableName, s)
 }
 
-func (b *Base) ForUpdateSQL(query string) string {
+// ForUpdateSQL returns for updateSQL
+func (db *Base) ForUpdateSQL(query string) string {
 	return query + " FOR UPDATE"
 }
 
-func (b *Base) SetParams(params map[string]string) {
+// SetParams set params
+func (db *Base) SetParams(params map[string]string) {
 }
 
 var (
@@ -206,6 +215,7 @@ func regDrvsNDialects() bool {
 		"postgres": {"postgres", func() Driver { return &pqDriver{} }, func() Dialect { return &postgres{} }},
 		"pgx":      {"postgres", func() Driver { return &pqDriverPgx{} }, func() Dialect { return &postgres{} }},
 		"sqlite3":  {"sqlite3", func() Driver { return &sqlite3Driver{} }, func() Dialect { return &sqlite3{} }},
+		"sqlite":   {"sqlite3", func() Driver { return &sqlite3Driver{} }, func() Dialect { return &sqlite3{} }},
 		"oci8":     {"oracle", func() Driver { return &oci8Driver{} }, func() Dialect { return &oracle{} }},
 		"goracle":  {"oracle", func() Driver { return &goracleDriver{} }, func() Dialect { return &oracle{} }},
 	}
diff --git a/dialects/driver.go b/dialects/driver.go
index ae3afe42..bb46a936 100644
--- a/dialects/driver.go
+++ b/dialects/driver.go
@@ -8,6 +8,7 @@ import (
 	"fmt"
 )
 
+// Driver represents a database driver
 type Driver interface {
 	Parse(string, string) (*URI, error)
 }
@@ -16,6 +17,7 @@ var (
 	drivers = map[string]Driver{}
 )
 
+// RegisterDriver register a driver
 func RegisterDriver(driverName string, driver Driver) {
 	if driver == nil {
 		panic("core: Register driver is nil")
@@ -26,10 +28,12 @@ func RegisterDriver(driverName string, driver Driver) {
 	drivers[driverName] = driver
 }
 
+// QueryDriver query a driver with name
 func QueryDriver(driverName string) Driver {
 	return drivers[driverName]
 }
 
+// RegisteredDriverSize returned all drivers's length
 func RegisteredDriverSize() int {
 	return len(drivers)
 }
@@ -38,7 +42,7 @@ func RegisteredDriverSize() int {
 func OpenDialect(driverName, connstr string) (Dialect, error) {
 	driver := QueryDriver(driverName)
 	if driver == nil {
-		return nil, fmt.Errorf("Unsupported driver name: %v", driverName)
+		return nil, fmt.Errorf("unsupported driver name: %v", driverName)
 	}
 
 	uri, err := driver.Parse(driverName, connstr)
@@ -48,7 +52,7 @@ func OpenDialect(driverName, connstr string) (Dialect, error) {
 
 	dialect := QueryDialect(uri.DBType)
 	if dialect == nil {
-		return nil, fmt.Errorf("Unsupported dialect type: %v", uri.DBType)
+		return nil, fmt.Errorf("unsupported dialect type: %v", uri.DBType)
 	}
 
 	dialect.Init(uri)
diff --git a/dialects/filter.go b/dialects/filter.go
index 6968b6ce..2a36a731 100644
--- a/dialects/filter.go
+++ b/dialects/filter.go
@@ -38,6 +38,7 @@ func convertQuestionMark(sql, prefix string, start int) string {
 	return buf.String()
 }
 
+// Do implements Filter
 func (s *SeqFilter) Do(sql string) string {
 	return convertQuestionMark(sql, s.Prefix, s.Start)
 }
diff --git a/dialects/mssql.go b/dialects/mssql.go
index 8ef924b8..15d1cd06 100644
--- a/dialects/mssql.go
+++ b/dialects/mssql.go
@@ -214,13 +214,45 @@ var (
 
 type mssql struct {
 	Base
+	defaultVarchar string
+	defaultChar    string
 }
 
 func (db *mssql) Init(uri *URI) error {
 	db.quoter = mssqlQuoter
+	db.defaultChar = "CHAR"
+	db.defaultVarchar = "VARCHAR"
 	return db.Base.Init(db, uri)
 }
 
+func (db *mssql) SetParams(params map[string]string) {
+	defaultVarchar, ok := params["DEFAULT_VARCHAR"]
+	if ok {
+		var t = strings.ToUpper(defaultVarchar)
+		switch t {
+		case "NVARCHAR", "VARCHAR":
+			db.defaultVarchar = t
+		default:
+			db.defaultVarchar = "VARCHAR"
+		}
+	} else {
+		db.defaultVarchar = "VARCHAR"
+	}
+
+	defaultChar, ok := params["DEFAULT_CHAR"]
+	if ok {
+		var t = strings.ToUpper(defaultChar)
+		switch t {
+		case "NCHAR", "CHAR":
+			db.defaultChar = t
+		default:
+			db.defaultChar = "CHAR"
+		}
+	} else {
+		db.defaultChar = "CHAR"
+	}
+}
+
 func (db *mssql) SQLType(c *schemas.Column) string {
 	var res string
 	switch t := c.SQLType.Name; t {
@@ -231,6 +263,7 @@ func (db *mssql) SQLType(c *schemas.Column) string {
 		} else if strings.EqualFold(c.Default, "false") {
 			c.Default = "0"
 		}
+		return res
 	case schemas.Serial:
 		c.IsAutoIncrement = true
 		c.IsPrimaryKey = true
@@ -251,10 +284,10 @@ func (db *mssql) SQLType(c *schemas.Column) string {
 	case schemas.TimeStampz:
 		res = "DATETIMEOFFSET"
 		c.Length = 7
-	case schemas.MediumInt:
+	case schemas.MediumInt, schemas.UnsignedInt:
 		res = schemas.Int
 	case schemas.Text, schemas.MediumText, schemas.TinyText, schemas.LongText, schemas.Json:
-		res = schemas.Varchar + "(MAX)"
+		res = db.defaultVarchar + "(MAX)"
 	case schemas.Double:
 		res = schemas.Real
 	case schemas.Uuid:
@@ -263,15 +296,35 @@ func (db *mssql) SQLType(c *schemas.Column) string {
 	case schemas.TinyInt:
 		res = schemas.TinyInt
 		c.Length = 0
-	case schemas.BigInt:
+	case schemas.BigInt, schemas.UnsignedBigInt:
 		res = schemas.BigInt
 		c.Length = 0
+	case schemas.NVarchar:
+		res = t
+		if c.Length == -1 {
+			res += "(MAX)"
+		}
+	case schemas.Varchar:
+		res = db.defaultVarchar
+		if c.Length == -1 {
+			res += "(MAX)"
+		}
+	case schemas.Char:
+		res = db.defaultChar
+		if c.Length == -1 {
+			res += "(MAX)"
+		}
+	case schemas.NChar:
+		res = t
+		if c.Length == -1 {
+			res += "(MAX)"
+		}
 	default:
 		res = t
 	}
 
-	if res == schemas.Int {
-		return schemas.Int
+	if res == schemas.Int || res == schemas.Bit || res == schemas.DateTime {
+		return res
 	}
 
 	hasLen1 := (c.Length > 0)
@@ -317,6 +370,11 @@ func (db *mssql) DropTableSQL(tableName string) (string, bool) {
 		"DROP TABLE \"%s\"", tableName, tableName), true
 }
 
+func (db *mssql) ModifyColumnSQL(tableName string, col *schemas.Column) string {
+	s, _ := ColumnString(db.dialect, col, false)
+	return fmt.Sprintf("ALTER TABLE %s ALTER COLUMN %s", tableName, s)
+}
+
 func (db *mssql) IndexCheckSQL(tableName, idxName string) (string, []interface{}) {
 	args := []interface{}{idxName}
 	sql := "select name from sysindexes where id=object_id('" + tableName + "') and name=?"
@@ -389,8 +447,18 @@ func (db *mssql) GetColumns(queryer core.Queryer, ctx context.Context, tableName
 			col.SQLType = schemas.SQLType{Name: schemas.TimeStampz, DefaultLength: 0, DefaultLength2: 0}
 		case "NVARCHAR":
 			col.SQLType = schemas.SQLType{Name: schemas.NVarchar, DefaultLength: 0, DefaultLength2: 0}
+			if col.Length > 0 {
+				col.Length /= 2
+				col.Length2 /= 2
+			}
 		case "IMAGE":
 			col.SQLType = schemas.SQLType{Name: schemas.VarBinary, DefaultLength: 0, DefaultLength2: 0}
+		case "NCHAR":
+			if col.Length > 0 {
+				col.Length /= 2
+				col.Length2 /= 2
+			}
+			fallthrough
 		default:
 			if _, ok := schemas.SqlTypes[ct]; ok {
 				col.SQLType = schemas.SQLType{Name: ct, DefaultLength: 0, DefaultLength2: 0}
@@ -472,7 +540,7 @@ WHERE IXS.TYPE_DESC='NONCLUSTERED' and OBJECT_NAME(IXS.OBJECT_ID) =?
 
 		colName = strings.Trim(colName, "` ")
 		var isRegular bool
-		if strings.HasPrefix(indexName, "IDX_"+tableName) || strings.HasPrefix(indexName, "UQE_"+tableName) {
+		if (strings.HasPrefix(indexName, "IDX_"+tableName) || strings.HasPrefix(indexName, "UQE_"+tableName)) && len(indexName) > (5+len(tableName)) {
 			indexName = indexName[5+len(tableName):]
 			isRegular = true
 		}
diff --git a/dialects/mysql.go b/dialects/mysql.go
index f9a2e943..2b530daf 100644
--- a/dialects/mysql.go
+++ b/dialects/mysql.go
@@ -254,6 +254,10 @@ func (db *mysql) SQLType(c *schemas.Column) string {
 		c.Length = 40
 	case schemas.Json:
 		res = schemas.Text
+	case schemas.UnsignedInt:
+		res = schemas.Int
+	case schemas.UnsignedBigInt:
+		res = schemas.BigInt
 	default:
 		res = t
 	}
@@ -271,6 +275,11 @@ func (db *mysql) SQLType(c *schemas.Column) string {
 	} else if hasLen1 {
 		res += "(" + strconv.Itoa(c.Length) + ")"
 	}
+
+	if c.SQLType.Name == schemas.UnsignedBigInt || c.SQLType.Name == schemas.UnsignedInt {
+		res += " UNSIGNED"
+	}
+
 	return res
 }
 
@@ -307,9 +316,17 @@ func (db *mysql) AddColumnSQL(tableName string, col *schemas.Column) string {
 
 func (db *mysql) GetColumns(queryer core.Queryer, ctx context.Context, tableName string) ([]string, map[string]*schemas.Column, error) {
 	args := []interface{}{db.uri.DBName, tableName}
+	alreadyQuoted := "(INSTR(VERSION(), 'maria') > 0 && " +
+		"(SUBSTRING_INDEX(VERSION(), '.', 1) > 10 || " +
+		"(SUBSTRING_INDEX(VERSION(), '.', 1) = 10 && " +
+		"(SUBSTRING_INDEX(SUBSTRING(VERSION(), 4), '.', 1) > 2 || " +
+		"(SUBSTRING_INDEX(SUBSTRING(VERSION(), 4), '.', 1) = 2 && " +
+		"SUBSTRING_INDEX(SUBSTRING(VERSION(), 6), '-', 1) >= 7)))))"
 	s := "SELECT `COLUMN_NAME`, `IS_NULLABLE`, `COLUMN_DEFAULT`, `COLUMN_TYPE`," +
-		" `COLUMN_KEY`, `EXTRA`,`COLUMN_COMMENT` FROM `INFORMATION_SCHEMA`.`COLUMNS` WHERE `TABLE_SCHEMA` = ? AND `TABLE_NAME` = ?" +
-		" ORDER BY `INFORMATION_SCHEMA`.`COLUMNS`.ORDINAL_POSITION"
+		" `COLUMN_KEY`, `EXTRA`, `COLUMN_COMMENT`, " +
+		alreadyQuoted + " AS NEEDS_QUOTE " +
+		"FROM `INFORMATION_SCHEMA`.`COLUMNS` WHERE `TABLE_SCHEMA` = ? AND `TABLE_NAME` = ?" +
+		" ORDER BY `COLUMNS`.ORDINAL_POSITION"
 
 	rows, err := queryer.QueryContext(ctx, s, args...)
 	if err != nil {
@@ -323,27 +340,35 @@ func (db *mysql) GetColumns(queryer core.Queryer, ctx context.Context, tableName
 		col := new(schemas.Column)
 		col.Indexes = make(map[string]int)
 
-		var columnName, isNullable, colType, colKey, extra, comment string
+		var columnName, nullableStr, colType, colKey, extra, comment string
+		var alreadyQuoted, isUnsigned bool
 		var colDefault *string
-		err = rows.Scan(&columnName, &isNullable, &colDefault, &colType, &colKey, &extra, &comment)
+		err = rows.Scan(&columnName, &nullableStr, &colDefault, &colType, &colKey, &extra, &comment, &alreadyQuoted)
 		if err != nil {
 			return nil, nil, err
 		}
 		col.Name = strings.Trim(columnName, "` ")
 		col.Comment = comment
-		if "YES" == isNullable {
+		if nullableStr == "YES" {
 			col.Nullable = true
 		}
 
-		if colDefault != nil {
+		if colDefault != nil && (!alreadyQuoted || *colDefault != "NULL") {
 			col.Default = *colDefault
 			col.DefaultIsEmpty = false
 		} else {
 			col.DefaultIsEmpty = true
 		}
 
+		fields := strings.Fields(colType)
+		if len(fields) == 2 && fields[1] == "unsigned" {
+			isUnsigned = true
+		}
+		colType = fields[0]
 		cts := strings.Split(colType, "(")
 		colName := cts[0]
+		// Remove the /* mariadb-5.3 */ suffix from coltypes
+		colName = strings.TrimSuffix(colName, "/* mariadb-5.3 */")
 		colType = strings.ToUpper(colName)
 		var len1, len2 int
 		if len(cts) == 2 {
@@ -378,11 +403,8 @@ func (db *mysql) GetColumns(queryer core.Queryer, ctx context.Context, tableName
 				}
 			}
 		}
-		if colType == "FLOAT UNSIGNED" {
-			colType = "FLOAT"
-		}
-		if colType == "DOUBLE UNSIGNED" {
-			colType = "DOUBLE"
+		if isUnsigned {
+			colType = "UNSIGNED " + colType
 		}
 		col.Length = len1
 		col.Length2 = len2
@@ -404,9 +426,9 @@ func (db *mysql) GetColumns(queryer core.Queryer, ctx context.Context, tableName
 		}
 
 		if !col.DefaultIsEmpty {
-			if col.SQLType.IsText() {
+			if !alreadyQuoted && col.SQLType.IsText() {
 				col.Default = "'" + col.Default + "'"
-			} else if col.SQLType.IsTime() && col.Default != "CURRENT_TIMESTAMP" {
+			} else if col.SQLType.IsTime() && !alreadyQuoted && col.Default != "CURRENT_TIMESTAMP" {
 				col.Default = "'" + col.Default + "'"
 			}
 		}
diff --git a/dialects/postgres.go b/dialects/postgres.go
index 1996c49d..e76e5b7e 100644
--- a/dialects/postgres.go
+++ b/dialects/postgres.go
@@ -824,6 +824,11 @@ func (db *postgres) SetQuotePolicy(quotePolicy QuotePolicy) {
 	}
 }
 
+// FormatBytes formats bytes
+func (db *postgres) FormatBytes(bs []byte) string {
+	return fmt.Sprintf("E'\\x%x'", bs)
+}
+
 func (db *postgres) SQLType(c *schemas.Column) string {
 	var res string
 	switch t := c.SQLType.Name; t {
@@ -833,12 +838,12 @@ func (db *postgres) SQLType(c *schemas.Column) string {
 	case schemas.Bit:
 		res = schemas.Boolean
 		return res
-	case schemas.MediumInt, schemas.Int, schemas.Integer:
+	case schemas.MediumInt, schemas.Int, schemas.Integer, schemas.UnsignedInt:
 		if c.IsAutoIncrement {
 			return schemas.Serial
 		}
 		return schemas.Integer
-	case schemas.BigInt:
+	case schemas.BigInt, schemas.UnsignedBigInt:
 		if c.IsAutoIncrement {
 			return schemas.BigSerial
 		}
@@ -857,6 +862,8 @@ func (db *postgres) SQLType(c *schemas.Column) string {
 		res = schemas.Real
 	case schemas.TinyText, schemas.MediumText, schemas.LongText:
 		res = schemas.Text
+	case schemas.NChar:
+		res = schemas.Char
 	case schemas.NVarchar:
 		res = schemas.Varchar
 	case schemas.Uuid:
@@ -1015,7 +1022,7 @@ WHERE n.nspname= s.table_schema AND c.relkind = 'r'::char AND c.relname = $1%s A
 
 	schema := db.getSchema()
 	if schema != "" {
-		s = fmt.Sprintf(s, "AND s.table_schema = $2")
+		s = fmt.Sprintf(s, " AND s.table_schema = $2")
 		args = append(args, schema)
 	} else {
 		s = fmt.Sprintf(s, "")
@@ -1050,6 +1057,10 @@ WHERE n.nspname= s.table_schema AND c.relkind = 'r'::char AND c.relname = $1%s A
 			}
 		}
 
+		if colDefault != nil && *colDefault == "unique_rowid()" { // ignore the system column added by cockroach
+			continue
+		}
+
 		col.Name = strings.Trim(colName, `" `)
 
 		if colDefault != nil {
@@ -1086,8 +1097,10 @@ WHERE n.nspname= s.table_schema AND c.relkind = 'r'::char AND c.relname = $1%s A
 		col.Nullable = (isNullable == "YES")
 
 		switch strings.ToLower(dataType) {
-		case "character varying", "character", "string":
+		case "character varying", "string":
 			col.SQLType = schemas.SQLType{Name: schemas.Varchar, DefaultLength: 0, DefaultLength2: 0}
+		case "character":
+			col.SQLType = schemas.SQLType{Name: schemas.Char, DefaultLength: 0, DefaultLength2: 0}
 		case "timestamp without time zone":
 			col.SQLType = schemas.SQLType{Name: schemas.DateTime, DefaultLength: 0, DefaultLength2: 0}
 		case "timestamp with time zone":
diff --git a/dialects/sqlite3.go b/dialects/sqlite3.go
index 0e910934..82683606 100644
--- a/dialects/sqlite3.go
+++ b/dialects/sqlite3.go
@@ -193,7 +193,8 @@ func (db *sqlite3) SQLType(c *schemas.Column) string {
 	case schemas.Char, schemas.Varchar, schemas.NVarchar, schemas.TinyText,
 		schemas.Text, schemas.MediumText, schemas.LongText, schemas.Json:
 		return schemas.Text
-	case schemas.Bit, schemas.TinyInt, schemas.SmallInt, schemas.MediumInt, schemas.Int, schemas.Integer, schemas.BigInt:
+	case schemas.Bit, schemas.TinyInt, schemas.SmallInt, schemas.MediumInt, schemas.Int, schemas.Integer, schemas.BigInt,
+		schemas.UnsignedBigInt, schemas.UnsignedInt:
 		return schemas.Integer
 	case schemas.Float, schemas.Double, schemas.Real:
 		return schemas.Real
@@ -483,7 +484,7 @@ func (db *sqlite3) GetIndexes(queryer core.Queryer, ctx context.Context, tableNa
 			continue
 		}
 
-		indexName := strings.Trim(sql[nNStart+6:nNEnd], "` []")
+		indexName := strings.Trim(strings.TrimSpace(sql[nNStart+6:nNEnd]), "`[]'\"")
 		var isRegular bool
 		if strings.HasPrefix(indexName, "IDX_"+tableName) || strings.HasPrefix(indexName, "UQE_"+tableName) {
 			index.Name = indexName[5+len(tableName):]
diff --git a/dialects/time.go b/dialects/time.go
index b0394745..5aee0c10 100644
--- a/dialects/time.go
+++ b/dialects/time.go
@@ -19,7 +19,11 @@ func FormatTime(dialect Dialect, sqlTypeName string, t time.Time) (v interface{}
 	case schemas.Date:
 		v = t.Format("2006-01-02")
 	case schemas.DateTime, schemas.TimeStamp, schemas.Varchar: // !DarthPestilane! format time when sqlTypeName is schemas.Varchar.
-		v = t.Format("2006-01-02 15:04:05")
+		if dialect.URI().DBType == schemas.ORACLE {
+			v = t
+		} else {
+			v = t.Format("2006-01-02 15:04:05")
+		}
 	case schemas.TimeStampz:
 		if dialect.URI().DBType == schemas.MSSQL {
 			v = t.Format("2006-01-02T15:04:05.9999999Z07:00")
@@ -34,6 +38,7 @@ func FormatTime(dialect Dialect, sqlTypeName string, t time.Time) (v interface{}
 	return
 }
 
+// FormatColumnTime format column time
 func FormatColumnTime(dialect Dialect, defaultTimeZone *time.Location, col *schemas.Column, t time.Time) (v interface{}) {
 	if t.IsZero() {
 		if col.Nullable {
diff --git a/engine.go b/engine.go
index 7399f41a..d49eea9a 100644
--- a/engine.go
+++ b/engine.go
@@ -21,6 +21,7 @@ import (
 	"xorm.io/xorm/contexts"
 	"xorm.io/xorm/core"
 	"xorm.io/xorm/dialects"
+	"xorm.io/xorm/internal/json"
 	"xorm.io/xorm/internal/utils"
 	"xorm.io/xorm/log"
 	"xorm.io/xorm/names"
@@ -61,6 +62,10 @@ func NewEngine(driverName string, dataSourceName string) (*Engine, error) {
 		return nil, err
 	}
 
+	return newEngine(driverName, dataSourceName, dialect, db)
+}
+
+func newEngine(driverName, dataSourceName string, dialect dialects.Dialect, db *core.DB) (*Engine, error) {
 	cacherMgr := caches.NewManager()
 	mapper := names.NewCacheMapper(new(names.SnakeMapper))
 	tagParser := tags.NewParser("xorm", dialect, mapper, mapper, cacherMgr)
@@ -88,7 +93,7 @@ func NewEngine(driverName string, dataSourceName string) (*Engine, error) {
 	engine.SetLogger(log.NewLoggerAdapter(logger))
 
 	runtime.SetFinalizer(engine, func(engine *Engine) {
-		engine.Close()
+		_ = engine.Close()
 	})
 
 	return engine, nil
@@ -101,6 +106,23 @@ func NewEngineWithParams(driverName string, dataSourceName string, params map[st
 	return engine, err
 }
 
+// NewEngineWithDB new a db manager with db. The params will be passed to db.
+func NewEngineWithDB(driverName string, dataSourceName string, db *core.DB) (*Engine, error) {
+	dialect, err := dialects.OpenDialect(driverName, dataSourceName)
+	if err != nil {
+		return nil, err
+	}
+	return newEngine(driverName, dataSourceName, dialect, db)
+}
+
+// NewEngineWithDialectAndDB new a db manager according to the parameter.
+// If you do not want to use your own dialect or db, please use NewEngine.
+// For creating dialect, you can call dialects.OpenDialect. And, for creating db,
+// you can call core.Open or core.FromDB.
+func NewEngineWithDialectAndDB(driverName, dataSourceName string, dialect dialects.Dialect, db *core.DB) (*Engine, error) {
+	return newEngine(driverName, dataSourceName, dialect, db)
+}
+
 // EnableSessionID if enable session id
 func (engine *Engine) EnableSessionID(enable bool) {
 	engine.logSessionID = enable
@@ -143,10 +165,12 @@ func (engine *Engine) Logger() log.ContextLogger {
 func (engine *Engine) SetLogger(logger interface{}) {
 	var realLogger log.ContextLogger
 	switch t := logger.(type) {
-	case log.Logger:
-		realLogger = log.NewLoggerAdapter(t)
 	case log.ContextLogger:
 		realLogger = t
+	case log.Logger:
+		realLogger = log.NewLoggerAdapter(t)
+	default:
+		panic("logger should implement either log.ContextLogger or log.Logger")
 	}
 	engine.logger = realLogger
 	engine.DB().Logger = realLogger
@@ -188,6 +212,11 @@ func (engine *Engine) SetColumnMapper(mapper names.Mapper) {
 	engine.tagParser.SetColumnMapper(mapper)
 }
 
+// SetTagIdentifier set the tag identifier
+func (engine *Engine) SetTagIdentifier(tagIdentifier string) {
+	engine.tagParser.SetIdentifier(tagIdentifier)
+}
+
 // Quote Use QuoteStr quote the string sql
 func (engine *Engine) Quote(value string) string {
 	value = strings.TrimSpace(value)
@@ -347,13 +376,16 @@ func (engine *Engine) loadTableInfo(table *schemas.Table) error {
 	var seq int
 	for _, index := range indexes {
 		for _, name := range index.Cols {
-			parts := strings.Split(name, " ")
+			parts := strings.Split(strings.TrimSpace(name), " ")
 			if len(parts) > 1 {
 				if parts[1] == "DESC" {
 					seq = 1
+				} else if parts[1] == "ASC" {
+					seq = 0
 				}
 			}
-			if col := table.GetColumn(parts[0]); col != nil {
+			var colName = strings.Trim(parts[0], `"`)
+			if col := table.GetColumn(colName); col != nil {
 				col.Indexes[index.Name] = index.Type
 			} else {
 				return fmt.Errorf("Unknown col %s seq %d, in index %v of table %v, columns %v", name, seq, index.Name, table.Name, table.ColumnsSeq())
@@ -412,6 +444,99 @@ func (engine *Engine) DumpTables(tables []*schemas.Table, w io.Writer, tp ...sch
 	return engine.dumpTables(tables, w, tp...)
 }
 
+func formatColumnValue(dstDialect dialects.Dialect, d interface{}, col *schemas.Column) string {
+	if d == nil {
+		return "NULL"
+	}
+
+	if dq, ok := d.(bool); ok && (dstDialect.URI().DBType == schemas.SQLITE ||
+		dstDialect.URI().DBType == schemas.MSSQL) {
+		if dq {
+			return "1"
+		}
+		return "0"
+	}
+
+	if col.SQLType.IsText() {
+		var v string
+		switch reflect.TypeOf(d).Kind() {
+		case reflect.Struct, reflect.Array, reflect.Slice, reflect.Map:
+			bytes, err := json.DefaultJSONHandler.Marshal(d)
+			if err != nil {
+				v = fmt.Sprintf("%s", d)
+			} else {
+				v = string(bytes)
+			}
+		default:
+			v = fmt.Sprintf("%s", d)
+		}
+
+		return "'" + strings.Replace(v, "'", "''", -1) + "'"
+	} else if col.SQLType.IsTime() {
+		if dstDialect.URI().DBType == schemas.MSSQL && col.SQLType.Name == schemas.DateTime {
+			if t, ok := d.(time.Time); ok {
+				return "'" + t.UTC().Format("2006-01-02 15:04:05") + "'"
+			}
+		}
+		var v = fmt.Sprintf("%s", d)
+		if strings.HasSuffix(v, " +0000 UTC") {
+			return fmt.Sprintf("'%s'", v[0:len(v)-len(" +0000 UTC")])
+		} else if strings.HasSuffix(v, " +0000 +0000") {
+			return fmt.Sprintf("'%s'", v[0:len(v)-len(" +0000 +0000")])
+		}
+		return "'" + strings.Replace(v, "'", "''", -1) + "'"
+	} else if col.SQLType.IsBlob() {
+		if reflect.TypeOf(d).Kind() == reflect.Slice {
+			return fmt.Sprintf("%s", dstDialect.FormatBytes(d.([]byte)))
+		} else if reflect.TypeOf(d).Kind() == reflect.String {
+			return fmt.Sprintf("'%s'", d.(string))
+		}
+	} else if col.SQLType.IsNumeric() {
+		switch reflect.TypeOf(d).Kind() {
+		case reflect.Slice:
+			if col.SQLType.Name == schemas.Bool {
+				return fmt.Sprintf("%v", strconv.FormatBool(d.([]byte)[0] != byte('0')))
+			}
+			return fmt.Sprintf("%s", string(d.([]byte)))
+		case reflect.Int16, reflect.Int8, reflect.Int32, reflect.Int64, reflect.Int:
+			if col.SQLType.Name == schemas.Bool {
+				v := reflect.ValueOf(d).Int() > 0
+				if dstDialect.URI().DBType == schemas.SQLITE {
+					if v {
+						return "1"
+					}
+					return "0"
+				}
+				return fmt.Sprintf("%v", strconv.FormatBool(v))
+			}
+			return fmt.Sprintf("%d", d)
+		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+			if col.SQLType.Name == schemas.Bool {
+				v := reflect.ValueOf(d).Uint() > 0
+				if dstDialect.URI().DBType == schemas.SQLITE {
+					if v {
+						return "1"
+					}
+					return "0"
+				}
+				return fmt.Sprintf("%v", strconv.FormatBool(v))
+			}
+			return fmt.Sprintf("%d", d)
+		default:
+			return fmt.Sprintf("%v", d)
+		}
+	}
+
+	s := fmt.Sprintf("%v", d)
+	if strings.Contains(s, ":") || strings.Contains(s, "-") {
+		if strings.HasSuffix(s, " +0000 UTC") {
+			return fmt.Sprintf("'%s'", s[0:len(s)-len(" +0000 UTC")])
+		}
+		return fmt.Sprintf("'%s'", s)
+	}
+	return s
+}
+
 // dumpTables dump database all table structs and data to w with specify db type
 func (engine *Engine) dumpTables(tables []*schemas.Table, w io.Writer, tp ...schemas.DBType) error {
 	var dstDialect dialects.Dialect
@@ -424,9 +549,14 @@ func (engine *Engine) dumpTables(tables []*schemas.Table, w io.Writer, tp ...sch
 		}
 
 		uri := engine.dialect.URI()
-		destURI := *uri
+		destURI := dialects.URI{
+			DBType: tp[0],
+			DBName: uri.DBName,
+		}
 		dstDialect.Init(&destURI)
 	}
+	cacherMgr := caches.NewManager()
+	dstTableCache := tags.NewParser("xorm", dstDialect, engine.GetTableMapper(), engine.GetColumnMapper(), cacherMgr)
 
 	_, err := io.WriteString(w, fmt.Sprintf("/*Generated by xorm %s, from %s to %s*/\n\n",
 		time.Now().In(engine.TZLocation).Format("2006-01-02 15:04:05"), engine.dialect.URI().DBType, dstDialect.URI().DBType))
@@ -435,9 +565,18 @@ func (engine *Engine) dumpTables(tables []*schemas.Table, w io.Writer, tp ...sch
 	}
 
 	for i, table := range tables {
-		tableName := table.Name
+		dstTable := table
+		if table.Type != nil {
+			dstTable, err = dstTableCache.Parse(reflect.New(table.Type).Elem())
+			if err != nil {
+				engine.logger.Errorf("Unable to infer table for %s in new dialect. Error: %v", table.Name)
+				dstTable = table
+			}
+		}
+
+		dstTableName := dstTable.Name
 		if dstDialect.URI().Schema != "" {
-			tableName = fmt.Sprintf("%s.%s", dstDialect.URI().Schema, table.Name)
+			dstTableName = fmt.Sprintf("%s.%s", dstDialect.URI().Schema, dstTable.Name)
 		}
 		originalTableName := table.Name
 		if engine.dialect.URI().Schema != "" {
@@ -449,27 +588,30 @@ func (engine *Engine) dumpTables(tables []*schemas.Table, w io.Writer, tp ...sch
 				return err
 			}
 		}
-		sqls, _ := dstDialect.CreateTableSQL(table, tableName)
+
+		sqls, _ := dstDialect.CreateTableSQL(dstTable, dstTableName)
 		for _, s := range sqls {
 			_, err = io.WriteString(w, s+";\n")
 			if err != nil {
 				return err
 			}
 		}
-		if len(table.PKColumns()) > 0 && dstDialect.URI().DBType == schemas.MSSQL {
-			fmt.Fprintf(w, "SET IDENTITY_INSERT [%s] ON;\n", table.Name)
+		if len(dstTable.PKColumns()) > 0 && dstDialect.URI().DBType == schemas.MSSQL {
+			fmt.Fprintf(w, "SET IDENTITY_INSERT [%s] ON;\n", dstTable.Name)
 		}
 
-		for _, index := range table.Indexes {
-			_, err = io.WriteString(w, dstDialect.CreateIndexSQL(table.Name, index)+";\n")
+		for _, index := range dstTable.Indexes {
+			_, err = io.WriteString(w, dstDialect.CreateIndexSQL(dstTable.Name, index)+";\n")
 			if err != nil {
 				return err
 			}
 		}
 
 		cols := table.ColumnsSeq()
+		dstCols := dstTable.ColumnsSeq()
+
 		colNames := engine.dialect.Quoter().Join(cols, ", ")
-		destColNames := dstDialect.Quoter().Join(cols, ", ")
+		destColNames := dstDialect.Quoter().Join(dstCols, ", ")
 
 		rows, err := engine.DB().QueryContext(engine.defaultContext, "SELECT "+colNames+" FROM "+engine.Quote(originalTableName))
 		if err != nil {
@@ -477,85 +619,83 @@ func (engine *Engine) dumpTables(tables []*schemas.Table, w io.Writer, tp ...sch
 		}
 		defer rows.Close()
 
-		for rows.Next() {
-			dest := make([]interface{}, len(cols))
-			err = rows.ScanSlice(&dest)
-			if err != nil {
-				return err
-			}
-
-			_, err = io.WriteString(w, "INSERT INTO "+dstDialect.Quoter().Quote(tableName)+" ("+destColNames+") VALUES (")
-			if err != nil {
-				return err
-			}
-
-			var temp string
-			for i, d := range dest {
-				col := table.GetColumn(cols[i])
-				if col == nil {
-					return errors.New("unknow column error")
+		if table.Type != nil {
+			sess := engine.NewSession()
+			defer sess.Close()
+			for rows.Next() {
+				beanValue := reflect.New(table.Type)
+				bean := beanValue.Interface()
+				fields, err := rows.Columns()
+				if err != nil {
+					return err
+				}
+				scanResults, err := sess.row2Slice(rows, fields, bean)
+				if err != nil {
+					return err
 				}
 
-				if d == nil {
-					temp += ", NULL"
-				} else if col.SQLType.IsText() || col.SQLType.IsTime() {
-					var v = fmt.Sprintf("%s", d)
-					if strings.HasSuffix(v, " +0000 UTC") {
-						temp += fmt.Sprintf(", '%s'", v[0:len(v)-len(" +0000 UTC")])
-					} else {
-						temp += ", '" + strings.Replace(v, "'", "''", -1) + "'"
+				dataStruct := utils.ReflectValue(bean)
+				_, err = sess.slice2Bean(scanResults, fields, bean, &dataStruct, table)
+				if err != nil {
+					return err
+				}
+
+				_, err = io.WriteString(w, "INSERT INTO "+dstDialect.Quoter().Quote(dstTableName)+" ("+destColNames+") VALUES (")
+				if err != nil {
+					return err
+				}
+
+				var temp string
+				for _, d := range dstCols {
+					col := table.GetColumn(d)
+					if col == nil {
+						return errors.New("unknown column error")
 					}
-				} else if col.SQLType.IsBlob() {
-					if reflect.TypeOf(d).Kind() == reflect.Slice {
-						temp += fmt.Sprintf(", %s", dstDialect.FormatBytes(d.([]byte)))
-					} else if reflect.TypeOf(d).Kind() == reflect.String {
-						temp += fmt.Sprintf(", '%s'", d.(string))
-					}
-				} else if col.SQLType.IsNumeric() {
-					switch reflect.TypeOf(d).Kind() {
-					case reflect.Slice:
-						if col.SQLType.Name == schemas.Bool {
-							temp += fmt.Sprintf(", %v", strconv.FormatBool(d.([]byte)[0] != byte('0')))
-						} else {
-							temp += fmt.Sprintf(", %s", string(d.([]byte)))
-						}
-					case reflect.Int16, reflect.Int8, reflect.Int32, reflect.Int64, reflect.Int:
-						if col.SQLType.Name == schemas.Bool {
-							temp += fmt.Sprintf(", %v", strconv.FormatBool(reflect.ValueOf(d).Int() > 0))
-						} else {
-							temp += fmt.Sprintf(", %v", d)
-						}
-					case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
-						if col.SQLType.Name == schemas.Bool {
-							temp += fmt.Sprintf(", %v", strconv.FormatBool(reflect.ValueOf(d).Uint() > 0))
-						} else {
-							temp += fmt.Sprintf(", %v", d)
-						}
-					default:
-						temp += fmt.Sprintf(", %v", d)
-					}
-				} else {
-					s := fmt.Sprintf("%v", d)
-					if strings.Contains(s, ":") || strings.Contains(s, "-") {
-						if strings.HasSuffix(s, " +0000 UTC") {
-							temp += fmt.Sprintf(", '%s'", s[0:len(s)-len(" +0000 UTC")])
-						} else {
-							temp += fmt.Sprintf(", '%s'", s)
-						}
-					} else {
-						temp += fmt.Sprintf(", %s", s)
+
+					fields := strings.Split(col.FieldName, ".")
+					field := dataStruct
+					for _, fieldName := range fields {
+						field = field.FieldByName(fieldName)
 					}
+					temp += "," + formatColumnValue(dstDialect, field.Interface(), col)
+				}
+				_, err = io.WriteString(w, temp[1:]+");\n")
+				if err != nil {
+					return err
 				}
 			}
-			_, err = io.WriteString(w, temp[2:]+");\n")
-			if err != nil {
-				return err
+		} else {
+			for rows.Next() {
+				dest := make([]interface{}, len(cols))
+				err = rows.ScanSlice(&dest)
+				if err != nil {
+					return err
+				}
+
+				_, err = io.WriteString(w, "INSERT INTO "+dstDialect.Quoter().Quote(dstTableName)+" ("+destColNames+") VALUES (")
+				if err != nil {
+					return err
+				}
+
+				var temp string
+				for i, d := range dest {
+					col := table.GetColumn(cols[i])
+					if col == nil {
+						return errors.New("unknow column error")
+					}
+
+					temp += "," + formatColumnValue(dstDialect, d, col)
+				}
+				_, err = io.WriteString(w, temp[1:]+");\n")
+				if err != nil {
+					return err
+				}
 			}
 		}
 
 		// FIXME: Hack for postgres
 		if dstDialect.URI().DBType == schemas.POSTGRES && table.AutoIncrColumn() != nil {
-			_, err = io.WriteString(w, "SELECT setval('"+tableName+"_id_seq', COALESCE((SELECT MAX("+table.AutoIncrColumn().Name+") + 1 FROM "+dstDialect.Quoter().Quote(tableName)+"), 1), false);\n")
+			_, err = io.WriteString(w, "SELECT setval('"+dstTableName+"_id_seq', COALESCE((SELECT MAX("+table.AutoIncrColumn().Name+") + 1 FROM "+dstDialect.Quoter().Quote(dstTableName)+"), 1), false);\n")
 			if err != nil {
 				return err
 			}
@@ -816,81 +956,11 @@ func (engine *Engine) IsTableExist(beanOrTableName interface{}) (bool, error) {
 	return session.IsTableExist(beanOrTableName)
 }
 
-// IDOf get id from one struct
-func (engine *Engine) IDOf(bean interface{}) (schemas.PK, error) {
-	return engine.IDOfV(reflect.ValueOf(bean))
-}
-
 // TableName returns table name with schema prefix if has
 func (engine *Engine) TableName(bean interface{}, includeSchema ...bool) string {
 	return dialects.FullTableName(engine.dialect, engine.GetTableMapper(), bean, includeSchema...)
 }
 
-// IDOfV get id from one value of struct
-func (engine *Engine) IDOfV(rv reflect.Value) (schemas.PK, error) {
-	return engine.idOfV(rv)
-}
-
-func (engine *Engine) idOfV(rv reflect.Value) (schemas.PK, error) {
-	v := reflect.Indirect(rv)
-	table, err := engine.tagParser.ParseWithCache(v)
-	if err != nil {
-		return nil, err
-	}
-
-	pk := make([]interface{}, len(table.PrimaryKeys))
-	for i, col := range table.PKColumns() {
-		var err error
-
-		fieldName := col.FieldName
-		for {
-			parts := strings.SplitN(fieldName, ".", 2)
-			if len(parts) == 1 {
-				break
-			}
-
-			v = v.FieldByName(parts[0])
-			if v.Kind() == reflect.Ptr {
-				v = v.Elem()
-			}
-			if v.Kind() != reflect.Struct {
-				return nil, ErrUnSupportedType
-			}
-			fieldName = parts[1]
-		}
-
-		pkField := v.FieldByName(fieldName)
-		switch pkField.Kind() {
-		case reflect.String:
-			pk[i], err = engine.idTypeAssertion(col, pkField.String())
-		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-			pk[i], err = engine.idTypeAssertion(col, strconv.FormatInt(pkField.Int(), 10))
-		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
-			// id of uint will be converted to int64
-			pk[i], err = engine.idTypeAssertion(col, strconv.FormatUint(pkField.Uint(), 10))
-		}
-
-		if err != nil {
-			return nil, err
-		}
-	}
-	return schemas.PK(pk), nil
-}
-
-func (engine *Engine) idTypeAssertion(col *schemas.Column, sid string) (interface{}, error) {
-	if col.SQLType.IsNumeric() {
-		n, err := strconv.ParseInt(sid, 10, 64)
-		if err != nil {
-			return nil, err
-		}
-		return n, nil
-	} else if col.SQLType.IsText() {
-		return sid, nil
-	} else {
-		return nil, errors.New("not supported")
-	}
-}
-
 // CreateIndexes create indexes
 func (engine *Engine) CreateIndexes(bean interface{}) error {
 	session := engine.NewSession()
@@ -1288,6 +1358,7 @@ func (engine *Engine) SetSchema(schema string) {
 	engine.dialect.URI().SetSchema(schema)
 }
 
+// AddHook adds a context Hook
 func (engine *Engine) AddHook(hook contexts.Hook) {
 	engine.db.AddHook(hook)
 }
@@ -1303,7 +1374,7 @@ func (engine *Engine) tbNameWithSchema(v string) string {
 	return dialects.TableNameWithSchema(engine.dialect, v)
 }
 
-// ContextHook creates a session with the context
+// Context creates a session with the context
 func (engine *Engine) Context(ctx context.Context) *Session {
 	session := engine.NewSession()
 	session.isAutoClose = true
@@ -1333,11 +1404,11 @@ func (engine *Engine) Transaction(f func(*Session) (interface{}, error)) (interf
 
 	result, err := f(session)
 	if err != nil {
-		return nil, err
+		return result, err
 	}
 
 	if err := session.Commit(); err != nil {
-		return nil, err
+		return result, err
 	}
 
 	return result, nil
diff --git a/engine_group.go b/engine_group.go
index cdd9dd44..3569690b 100644
--- a/engine_group.go
+++ b/engine_group.go
@@ -79,7 +79,7 @@ func (eg *EngineGroup) Close() error {
 	return nil
 }
 
-// ContextHook returned a group session
+// Context returned a group session
 func (eg *EngineGroup) Context(ctx context.Context) *Session {
 	sess := eg.NewSession()
 	sess.isAutoClose = true
@@ -144,6 +144,7 @@ func (eg *EngineGroup) SetLogger(logger interface{}) {
 	}
 }
 
+// AddHook adds Hook
 func (eg *EngineGroup) AddHook(hook contexts.Hook) {
 	eg.Engine.AddHook(hook)
 	for i := 0; i < len(eg.slaves); i++ {
@@ -167,6 +168,14 @@ func (eg *EngineGroup) SetMapper(mapper names.Mapper) {
 	}
 }
 
+// SetTagIdentifier set the tag identifier
+func (eg *EngineGroup) SetTagIdentifier(tagIdentifier string) {
+	eg.Engine.SetTagIdentifier(tagIdentifier)
+	for i := 0; i < len(eg.slaves); i++ {
+		eg.slaves[i].SetTagIdentifier(tagIdentifier)
+	}
+}
+
 // SetMaxIdleConns set the max idle connections on pool, default is 2
 func (eg *EngineGroup) SetMaxIdleConns(conns int) {
 	eg.Engine.DB().SetMaxIdleConns(conns)
diff --git a/go.mod b/go.mod
index ff42c0f7..f6e4af90 100644
--- a/go.mod
+++ b/go.mod
@@ -1,16 +1,16 @@
 module xorm.io/xorm
 
-go 1.11
+go 1.13
 
 require (
-	github.com/denisenkom/go-mssqldb v0.0.0-20190707035753-2be1aa521ff4
-	github.com/go-sql-driver/mysql v1.4.1
-	github.com/kr/pretty v0.1.0 // indirect
-	github.com/lib/pq v1.0.0
-	github.com/mattn/go-sqlite3 v1.10.0
+	github.com/denisenkom/go-mssqldb v0.9.0
+	github.com/go-sql-driver/mysql v1.5.0
+	github.com/json-iterator/go v1.1.11
+	github.com/lib/pq v1.7.0
+	github.com/mattn/go-sqlite3 v1.14.6
 	github.com/stretchr/testify v1.4.0
 	github.com/syndtr/goleveldb v1.0.0
 	github.com/ziutek/mymysql v1.5.4
-	google.golang.org/appengine v1.6.0 // indirect
-	xorm.io/builder v0.3.7
+	modernc.org/sqlite v1.10.1-0.20210314190707-798bbeb9bb84
+	xorm.io/builder v0.3.8
 )
diff --git a/go.sum b/go.sum
index 84f9126e..3c79850c 100644
--- a/go.sum
+++ b/go.sum
@@ -1,152 +1,97 @@
-cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
-cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
-cloud.google.com/go v0.37.4 h1:glPeL3BQJsbF6aIIYfZizMwc5LTYz250bDMjttbBGAU=
-cloud.google.com/go v0.37.4/go.mod h1:NHPJ89PdicEuT9hdPXMROBD91xc5uRDxsMtSB16k7hw=
 gitea.com/xorm/sqlfiddle v0.0.0-20180821085327-62ce714f951a h1:lSA0F4e9A2NcQSqGqTOXqu2aRi/XEQxDCBwM8yJtE6s=
 gitea.com/xorm/sqlfiddle v0.0.0-20180821085327-62ce714f951a/go.mod h1:EXuID2Zs0pAQhH8yz+DNjUbjppKQzKFAn28TMYPB6IU=
-github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
-github.com/Shopify/sarama v1.19.0/go.mod h1:FVkBWblsNy7DGZRfXLU0O9RCGt5g3g3yEuWXgklEdEo=
-github.com/Shopify/toxiproxy v2.1.4+incompatible/go.mod h1:OXgGpZ6Cli1/URJOF1DMxUHB2q5Ap20/P/eIdh4G0pI=
-github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
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+modernc.org/mathutil v1.2.2 h1:+yFk8hBprV+4c0U9GjFtL+dV3N8hOJ8JCituQcMShFY=
+modernc.org/mathutil v1.2.2/go.mod h1:mZW8CKdRPY1v87qxC/wUdX5O1qDzXMP5TH3wjfpga6E=
+modernc.org/memory v1.0.4 h1:utMBrFcpnQDdNsmM6asmyH/FM9TqLPS7XF7otpJmrwM=
+modernc.org/memory v1.0.4/go.mod h1:nV2OApxradM3/OVbs2/0OsP6nPfakXpi50C7dcoHXlc=
+modernc.org/opt v0.1.1 h1:/0RX92k9vwVeDXj+Xn23DKp2VJubL7k8qNffND6qn3A=
+modernc.org/opt v0.1.1/go.mod h1:WdSiB5evDcignE70guQKxYUl14mgWtbClRi5wmkkTX0=
+modernc.org/sqlite v1.10.1-0.20210314190707-798bbeb9bb84 h1:rgEUzE849tFlHSoeCrKyS9cZAljC+DY7MdMHKq6R6sY=
+modernc.org/sqlite v1.10.1-0.20210314190707-798bbeb9bb84/go.mod h1:PGzq6qlhyYjL6uVbSgS6WoF7ZopTW/sI7+7p+mb4ZVU=
+modernc.org/strutil v1.1.0 h1:+1/yCzZxY2pZwwrsbH+4T7BQMoLQ9QiBshRC9eicYsc=
+modernc.org/strutil v1.1.0/go.mod h1:lstksw84oURvj9y3tn8lGvRxyRC1S2+g5uuIzNfIOBs=
+modernc.org/tcl v1.5.0 h1:euZSUNfE0Fd4W8VqXI1Ly1v7fqDJoBuAV88Ea+SnaSs=
+modernc.org/tcl v1.5.0/go.mod h1:gb57hj4pO8fRrK54zveIfFXBaMHK3SKJNWcmRw1cRzc=
+modernc.org/token v1.0.0 h1:a0jaWiNMDhDUtqOj09wvjWWAqd3q7WpBulmL9H2egsk=
+modernc.org/token v1.0.0/go.mod h1:UGzOrNV1mAFSEB63lOFHIpNRUVMvYTc6yu1SMY/XTDM=
+modernc.org/z v1.0.1-0.20210308123920-1f282aa71362/go.mod h1:8/SRk5C/HgiQWCgXdfpb+1RvhORdkz5sw72d3jjtyqA=
+modernc.org/z v1.0.1 h1:WyIDpEpAIx4Hel6q/Pcgj/VhaQV5XPJ2I6ryIYbjnpc=
+modernc.org/z v1.0.1/go.mod h1:8/SRk5C/HgiQWCgXdfpb+1RvhORdkz5sw72d3jjtyqA=
+xorm.io/builder v0.3.8 h1:P/wPgRqa9kX5uE0aA1/ukJ23u9KH0aSRpHLwDKXigSE=
+xorm.io/builder v0.3.8/go.mod h1:aUW0S9eb9VCaPohFCH3j7czOx1PMW3i1HrSzbLYGBSE=
diff --git a/integrations/engine_test.go b/integrations/engine_test.go
index 19c5285d..3b843f16 100644
--- a/integrations/engine_test.go
+++ b/integrations/engine_test.go
@@ -20,6 +20,7 @@ import (
 	_ "github.com/mattn/go-sqlite3"
 	"github.com/stretchr/testify/assert"
 	_ "github.com/ziutek/mymysql/godrv"
+	_ "modernc.org/sqlite"
 )
 
 func TestPing(t *testing.T) {
@@ -93,19 +94,23 @@ func TestDump(t *testing.T) {
 	assert.NoError(t, PrepareEngine())
 
 	type TestDumpStruct struct {
-		Id   int64
-		Name string
+		Id      int64
+		Name    string
+		IsMan   bool
+		Created time.Time `xorm:"created"`
 	}
 
 	assertSync(t, new(TestDumpStruct))
 
-	testEngine.Insert([]TestDumpStruct{
-		{Name: "1"},
+	cnt, err := testEngine.Insert([]TestDumpStruct{
+		{Name: "1", IsMan: true},
 		{Name: "2\n"},
 		{Name: "3;"},
 		{Name: "4\n;\n''"},
 		{Name: "5'\n"},
 	})
+	assert.NoError(t, err)
+	assert.EqualValues(t, 5, cnt)
 
 	fp := fmt.Sprintf("%v.sql", testEngine.Dialect().URI().DBType)
 	os.Remove(fp)
@@ -116,7 +121,7 @@ func TestDump(t *testing.T) {
 	sess := testEngine.NewSession()
 	defer sess.Close()
 	assert.NoError(t, sess.Begin())
-	_, err := sess.ImportFile(fp)
+	_, err = sess.ImportFile(fp)
 	assert.NoError(t, err)
 	assert.NoError(t, sess.Commit())
 
@@ -128,6 +133,49 @@ func TestDump(t *testing.T) {
 	}
 }
 
+func TestDumpTables(t *testing.T) {
+	assert.NoError(t, PrepareEngine())
+
+	type TestDumpTableStruct struct {
+		Id      int64
+		Name    string
+		IsMan   bool
+		Created time.Time `xorm:"created"`
+	}
+
+	assertSync(t, new(TestDumpTableStruct))
+
+	testEngine.Insert([]TestDumpTableStruct{
+		{Name: "1", IsMan: true},
+		{Name: "2\n"},
+		{Name: "3;"},
+		{Name: "4\n;\n''"},
+		{Name: "5'\n"},
+	})
+
+	fp := fmt.Sprintf("%v-table.sql", testEngine.Dialect().URI().DBType)
+	os.Remove(fp)
+	tb, err := testEngine.TableInfo(new(TestDumpTableStruct))
+	assert.NoError(t, err)
+	assert.NoError(t, testEngine.(*xorm.Engine).DumpTablesToFile([]*schemas.Table{tb}, fp))
+
+	assert.NoError(t, PrepareEngine())
+
+	sess := testEngine.NewSession()
+	defer sess.Close()
+	assert.NoError(t, sess.Begin())
+	_, err = sess.ImportFile(fp)
+	assert.NoError(t, err)
+	assert.NoError(t, sess.Commit())
+
+	for _, tp := range []schemas.DBType{schemas.SQLITE, schemas.MYSQL, schemas.POSTGRES, schemas.MSSQL} {
+		name := fmt.Sprintf("dump_%v-table.sql", tp)
+		t.Run(name, func(t *testing.T) {
+			assert.NoError(t, testEngine.(*xorm.Engine).DumpTablesToFile([]*schemas.Table{tb}, name, tp))
+		})
+	}
+}
+
 func TestSetSchema(t *testing.T) {
 	assert.NoError(t, PrepareEngine())
 
@@ -139,3 +187,16 @@ func TestSetSchema(t *testing.T) {
 		assert.EqualValues(t, oldSchema, testEngine.Dialect().URI().Schema)
 	}
 }
+
+func TestImport(t *testing.T) {
+	if testEngine.Dialect().URI().DBType != schemas.MYSQL {
+		t.Skip()
+		return
+	}
+	sess := testEngine.NewSession()
+	defer sess.Close()
+	assert.NoError(t, sess.Begin())
+	_, err := sess.ImportFile("./testdata/import1.sql")
+	assert.NoError(t, err)
+	assert.NoError(t, sess.Commit())
+}
diff --git a/integrations/session_delete_test.go b/integrations/session_delete_test.go
index f3565963..cc7e861d 100644
--- a/integrations/session_delete_test.go
+++ b/integrations/session_delete_test.go
@@ -97,6 +97,7 @@ func TestDeleted(t *testing.T) {
 	// Test normal Find()
 	var records1 []Deleted
 	err = testEngine.Where("`"+testEngine.GetColumnMapper().Obj2Table("Id")+"` > 0").Find(&records1, &Deleted{})
+	assert.NoError(t, err)
 	assert.EqualValues(t, 3, len(records1))
 
 	// Test normal Get()
@@ -132,6 +133,7 @@ func TestDeleted(t *testing.T) {
 	record2 := &Deleted{}
 	has, err = testEngine.ID(2).Get(record2)
 	assert.NoError(t, err)
+	assert.True(t, has)
 	assert.True(t, record2.DeletedAt.IsZero())
 
 	// Test find all records whatever `deleted`.
diff --git a/integrations/session_find_test.go b/integrations/session_find_test.go
index b9d722ba..f90b5317 100644
--- a/integrations/session_find_test.go
+++ b/integrations/session_find_test.go
@@ -502,13 +502,58 @@ func TestFindAndCountOneFunc(t *testing.T) {
 	assert.EqualValues(t, 1, cnt)
 
 	results = make([]FindAndCountStruct, 0, 1)
-	cnt, err = testEngine.Where("msg = ?", true).Limit(1).FindAndCount(&results)
+	cnt, err = testEngine.Where("1=1").Limit(1).FindAndCount(&results)
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, len(results))
+	assert.EqualValues(t, 2, cnt)
+	assert.EqualValues(t, FindAndCountStruct{
+		Id:      1,
+		Content: "111",
+		Msg:     false,
+	}, results[0])
+
+	results = make([]FindAndCountStruct, 0, 1)
+	cnt, err = testEngine.Where("1=1").Limit(1).FindAndCount(&results)
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, len(results))
+	assert.EqualValues(t, 2, cnt)
+	assert.EqualValues(t, FindAndCountStruct{
+		Id:      1,
+		Content: "111",
+		Msg:     false,
+	}, results[0])
+
+	results = make([]FindAndCountStruct, 0, 1)
+	cnt, err = testEngine.Where("1=1").Limit(1, 1).FindAndCount(&results)
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, len(results))
+	assert.EqualValues(t, 2, cnt)
+	assert.EqualValues(t, FindAndCountStruct{
+		Id:      2,
+		Content: "222",
+		Msg:     true,
+	}, results[0])
+
+	results = make([]FindAndCountStruct, 0, 1)
+	cnt, err = testEngine.Where("1=1").Limit(1, 1).FindAndCount(&results)
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, len(results))
+	assert.EqualValues(t, 2, cnt)
+	assert.EqualValues(t, FindAndCountStruct{
+		Id:      2,
+		Content: "222",
+		Msg:     true,
+	}, results[0])
+
+	results = make([]FindAndCountStruct, 0, 1)
+	cnt, err = testEngine.Where("msg = ?", true).Select("id, content, msg").
+		Limit(1).FindAndCount(&results)
 	assert.NoError(t, err)
 	assert.EqualValues(t, 1, len(results))
 	assert.EqualValues(t, 1, cnt)
 
 	results = make([]FindAndCountStruct, 0, 1)
-	cnt, err = testEngine.Where("msg = ?", true).Select("id, content, msg").
+	cnt, err = testEngine.Where("msg = ?", true).Cols("id", "content", "msg").
 		Limit(1).FindAndCount(&results)
 	assert.NoError(t, err)
 	assert.EqualValues(t, 1, len(results))
@@ -608,6 +653,31 @@ func TestFindAndCount2(t *testing.T) {
 	assert.EqualValues(t, 0, cnt)
 }
 
+type FindAndCountWithTableName struct {
+	Id   int64
+	Name string
+}
+
+func (FindAndCountWithTableName) TableName() string {
+	return "find_and_count_with_table_name1"
+}
+
+func TestFindAndCountWithTableName(t *testing.T) {
+	assert.NoError(t, PrepareEngine())
+	assertSync(t, new(FindAndCountWithTableName))
+
+	cnt, err := testEngine.Insert(&FindAndCountWithTableName{
+		Name: "1",
+	})
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, cnt)
+
+	var res []FindAndCountWithTableName
+	cnt, err = testEngine.FindAndCount(&res)
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, cnt)
+}
+
 type FindMapDevice struct {
 	Deviceid string `xorm:"pk"`
 	Status   int
diff --git a/integrations/session_get_test.go b/integrations/session_get_test.go
index 4e50f9ab..99db98fc 100644
--- a/integrations/session_get_test.go
+++ b/integrations/session_get_test.go
@@ -6,11 +6,13 @@ package integrations
 
 import (
 	"database/sql"
+	"errors"
 	"fmt"
 	"strconv"
 	"testing"
 	"time"
 
+	"xorm.io/xorm"
 	"xorm.io/xorm/contexts"
 	"xorm.io/xorm/schemas"
 
@@ -394,6 +396,60 @@ func TestJSONString(t *testing.T) {
 	assert.NoError(t, err)
 	assert.EqualValues(t, 1, len(jss))
 	assert.True(t, `["1","2"]` == jss[0].Content || `["1", "2"]` == jss[0].Content)
+
+	type JsonAnonymousStruct struct {
+		Id         int64
+		JsonString `xorm:"'json_string' JSON LONGTEXT"`
+	}
+
+	assertSync(t, new(JsonAnonymousStruct))
+
+	_, err = testEngine.Insert(&JsonAnonymousStruct{
+		JsonString: JsonString{
+			Content: "1",
+		},
+	})
+	assert.NoError(t, err)
+
+	var jas JsonAnonymousStruct
+	has, err = testEngine.Get(&jas)
+	assert.NoError(t, err)
+	assert.True(t, has)
+	assert.EqualValues(t, 1, jas.Id)
+	assert.EqualValues(t, "1", jas.Content)
+
+	var jass []JsonAnonymousStruct
+	err = testEngine.Find(&jass)
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, len(jass))
+	assert.EqualValues(t, "1", jass[0].Content)
+
+	type JsonStruct struct {
+		Id   int64
+		JSON JsonString `xorm:"'json_string' JSON LONGTEXT"`
+	}
+
+	assertSync(t, new(JsonStruct))
+
+	_, err = testEngine.Insert(&JsonStruct{
+		JSON: JsonString{
+			Content: "2",
+		},
+	})
+	assert.NoError(t, err)
+
+	var jst JsonStruct
+	has, err = testEngine.Get(&jst)
+	assert.NoError(t, err)
+	assert.True(t, has)
+	assert.EqualValues(t, 1, jst.Id)
+	assert.EqualValues(t, "2", jst.JSON.Content)
+
+	var jsts []JsonStruct
+	err = testEngine.Find(&jsts)
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, len(jsts))
+	assert.EqualValues(t, "2", jsts[0].JSON.Content)
 }
 
 func TestGetActionMapping(t *testing.T) {
@@ -696,3 +752,17 @@ func TestGetViaMapCond(t *testing.T) {
 	assert.NoError(t, err)
 	assert.False(t, has)
 }
+
+func TestGetNil(t *testing.T) {
+	type GetNil struct {
+		Id int64
+	}
+
+	assert.NoError(t, PrepareEngine())
+	assertSync(t, new(GetNil))
+
+	var gn *GetNil
+	has, err := testEngine.Get(gn)
+	assert.True(t, errors.Is(err, xorm.ErrObjectIsNil))
+	assert.False(t, has)
+}
diff --git a/integrations/session_schema_test.go b/integrations/session_schema_test.go
index 005b6619..1ef653ef 100644
--- a/integrations/session_schema_test.go
+++ b/integrations/session_schema_test.go
@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/stretchr/testify/assert"
+	"xorm.io/xorm/schemas"
 )
 
 func TestStoreEngine(t *testing.T) {
@@ -102,6 +103,9 @@ func TestSyncTable(t *testing.T) {
 	assert.NoError(t, err)
 	assert.EqualValues(t, 1, len(tables))
 	assert.EqualValues(t, "sync_table1", tables[0].Name)
+	tableInfo, err := testEngine.TableInfo(new(SyncTable1))
+	assert.NoError(t, err)
+	assert.EqualValues(t, testEngine.Dialect().SQLType(tables[0].GetColumn("name")), testEngine.Dialect().SQLType(tableInfo.GetColumn("name")))
 
 	assert.NoError(t, testEngine.Sync2(new(SyncTable2)))
 
@@ -109,6 +113,9 @@ func TestSyncTable(t *testing.T) {
 	assert.NoError(t, err)
 	assert.EqualValues(t, 1, len(tables))
 	assert.EqualValues(t, "sync_table1", tables[0].Name)
+	tableInfo, err = testEngine.TableInfo(new(SyncTable2))
+	assert.NoError(t, err)
+	assert.EqualValues(t, testEngine.Dialect().SQLType(tables[0].GetColumn("name")), testEngine.Dialect().SQLType(tableInfo.GetColumn("name")))
 
 	assert.NoError(t, testEngine.Sync2(new(SyncTable3)))
 
@@ -116,6 +123,9 @@ func TestSyncTable(t *testing.T) {
 	assert.NoError(t, err)
 	assert.EqualValues(t, 1, len(tables))
 	assert.EqualValues(t, "sync_table1", tables[0].Name)
+	tableInfo, err = testEngine.TableInfo(new(SyncTable3))
+	assert.NoError(t, err)
+	assert.EqualValues(t, testEngine.Dialect().SQLType(tables[0].GetColumn("name")), testEngine.Dialect().SQLType(tableInfo.GetColumn("name")))
 }
 
 func TestSyncTable2(t *testing.T) {
@@ -143,6 +153,63 @@ func TestSyncTable2(t *testing.T) {
 	assert.EqualValues(t, colMapper.Obj2Table("NewCol"), tables[0].Columns()[3].Name)
 }
 
+func TestSyncTable3(t *testing.T) {
+	type SyncTable5 struct {
+		Id         int64
+		Name       string
+		Text       string   `xorm:"TEXT"`
+		Char       byte     `xorm:"CHAR(1)"`
+		TenChar    [10]byte `xorm:"CHAR(10)"`
+		TenVarChar string   `xorm:"VARCHAR(10)"`
+	}
+
+	assert.NoError(t, PrepareEngine())
+
+	assert.NoError(t, testEngine.Sync2(new(SyncTable5)))
+
+	tables, err := testEngine.DBMetas()
+	assert.NoError(t, err)
+	tableInfo, err := testEngine.TableInfo(new(SyncTable5))
+	assert.NoError(t, err)
+	assert.EqualValues(t, testEngine.Dialect().SQLType(tableInfo.GetColumn("name")), testEngine.Dialect().SQLType(tables[0].GetColumn("name")))
+	assert.EqualValues(t, testEngine.Dialect().SQLType(tableInfo.GetColumn("text")), testEngine.Dialect().SQLType(tables[0].GetColumn("text")))
+	assert.EqualValues(t, testEngine.Dialect().SQLType(tableInfo.GetColumn("char")), testEngine.Dialect().SQLType(tables[0].GetColumn("char")))
+	assert.EqualValues(t, testEngine.Dialect().SQLType(tableInfo.GetColumn("ten_char")), testEngine.Dialect().SQLType(tables[0].GetColumn("ten_char")))
+	assert.EqualValues(t, testEngine.Dialect().SQLType(tableInfo.GetColumn("ten_var_char")), testEngine.Dialect().SQLType(tables[0].GetColumn("ten_var_char")))
+
+	if *doNVarcharTest {
+		var oldDefaultVarchar string
+		var oldDefaultChar string
+		oldDefaultVarchar, *defaultVarchar = *defaultVarchar, "nvarchar"
+		oldDefaultChar, *defaultChar = *defaultChar, "nchar"
+		testEngine.Dialect().SetParams(map[string]string{
+			"DEFAULT_VARCHAR": *defaultVarchar,
+			"DEFAULT_CHAR":    *defaultChar,
+		})
+		defer func() {
+			*defaultVarchar = oldDefaultVarchar
+			*defaultChar = oldDefaultChar
+			testEngine.Dialect().SetParams(map[string]string{
+				"DEFAULT_VARCHAR": *defaultVarchar,
+				"DEFAULT_CHAR":    *defaultChar,
+			})
+		}()
+		assert.NoError(t, PrepareEngine())
+
+		assert.NoError(t, testEngine.Sync2(new(SyncTable5)))
+
+		tables, err := testEngine.DBMetas()
+		assert.NoError(t, err)
+		tableInfo, err := testEngine.TableInfo(new(SyncTable5))
+		assert.NoError(t, err)
+		assert.EqualValues(t, testEngine.Dialect().SQLType(tableInfo.GetColumn("name")), testEngine.Dialect().SQLType(tables[0].GetColumn("name")))
+		assert.EqualValues(t, testEngine.Dialect().SQLType(tableInfo.GetColumn("text")), testEngine.Dialect().SQLType(tables[0].GetColumn("text")))
+		assert.EqualValues(t, testEngine.Dialect().SQLType(tableInfo.GetColumn("char")), testEngine.Dialect().SQLType(tables[0].GetColumn("char")))
+		assert.EqualValues(t, testEngine.Dialect().SQLType(tableInfo.GetColumn("ten_char")), testEngine.Dialect().SQLType(tables[0].GetColumn("ten_char")))
+		assert.EqualValues(t, testEngine.Dialect().SQLType(tableInfo.GetColumn("ten_var_char")), testEngine.Dialect().SQLType(tables[0].GetColumn("ten_var_char")))
+	}
+}
+
 func TestIsTableExist(t *testing.T) {
 	assert.NoError(t, PrepareEngine())
 
@@ -330,3 +397,30 @@ func TestSync2_Default(t *testing.T) {
 	assertSync(t, new(TestSync2Default))
 	assert.NoError(t, testEngine.Sync2(new(TestSync2Default)))
 }
+
+func TestModifyColum(t *testing.T) {
+	// Since SQLITE don't support modify column SQL, currrently just ignore
+	if testEngine.Dialect().URI().DBType == schemas.SQLITE {
+		return
+	}
+	type TestModifyColumn struct {
+		Id       int64
+		UserId   int64  `xorm:"default(1)"`
+		IsMember bool   `xorm:"default(true)"`
+		Name     string `xorm:"char(10)"`
+	}
+
+	assert.NoError(t, PrepareEngine())
+	assertSync(t, new(TestModifyColumn))
+
+	alterSQL := testEngine.Dialect().ModifyColumnSQL("test_modify_column", &schemas.Column{
+		Name: "name",
+		SQLType: schemas.SQLType{
+			Name: "VARCHAR",
+		},
+		Length:   16,
+		Nullable: false,
+	})
+	_, err := testEngine.Exec(alterSQL)
+	assert.NoError(t, err)
+}
diff --git a/integrations/session_test.go b/integrations/session_test.go
index bdf3278d..c3ef0513 100644
--- a/integrations/session_test.go
+++ b/integrations/session_test.go
@@ -54,3 +54,11 @@ func TestMustLogSQL(t *testing.T) {
 	_, err := testEngine.Table("userinfo").MustLogSQL(true).Get(new(Userinfo))
 	assert.NoError(t, err)
 }
+
+func TestEnableSessionId(t *testing.T) {
+	assert.NoError(t, PrepareEngine())
+	testEngine.EnableSessionID(true)
+	assertSync(t, new(Userinfo))
+	_, err := testEngine.Table("userinfo").MustLogSQL(true).Get(new(Userinfo))
+	assert.NoError(t, err)
+}
diff --git a/integrations/session_update_test.go b/integrations/session_update_test.go
index 8800246c..df0631c4 100644
--- a/integrations/session_update_test.go
+++ b/integrations/session_update_test.go
@@ -12,8 +12,10 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"xorm.io/xorm"
+	"xorm.io/xorm/internal/statements"
 	"xorm.io/xorm/internal/utils"
 	"xorm.io/xorm/names"
+	"xorm.io/xorm/schemas"
 )
 
 func TestUpdateMap(t *testing.T) {
@@ -39,6 +41,27 @@ func TestUpdateMap(t *testing.T) {
 	})
 	assert.NoError(t, err)
 	assert.EqualValues(t, 1, cnt)
+
+	cnt, err = testEngine.Table("update_table").ID(tb.Id).Update(map[string]interface{}{
+		"name": "test2",
+		"age":  36,
+	})
+	assert.Error(t, err)
+	assert.True(t, statements.IsIDConditionWithNoTableErr(err))
+	assert.EqualValues(t, 0, cnt)
+
+	cnt, err = testEngine.Table("update_table").Update(map[string]interface{}{
+		"name": "test2",
+		"age":  36,
+	}, &UpdateTable{
+		Id: tb.Id,
+	})
+	assert.NoError(t, err)
+	if testEngine.Dialect().URI().DBType == schemas.MYSQL {
+		assert.EqualValues(t, 0, cnt)
+	} else {
+		assert.EqualValues(t, 1, cnt)
+	}
 }
 
 func TestUpdateLimit(t *testing.T) {
@@ -179,6 +202,9 @@ func TestForUpdate(t *testing.T) {
 
 	// lock is NOT used
 	wg.Add(1)
+
+	wg2 := &sync.WaitGroup{}
+	wg2.Add(1)
 	go func() {
 		f3 := new(ForUpdate)
 		session3.Where("id = ?", 1)
@@ -192,10 +218,10 @@ func TestForUpdate(t *testing.T) {
 			t.Errorf("read lock failed")
 		}
 		wg.Done()
+		wg2.Done()
 	}()
 
-	// wait for go rountines
-	time.Sleep(50 * time.Millisecond)
+	wg2.Wait()
 
 	f := new(ForUpdate)
 	f.Name = "updated by session1"
@@ -988,7 +1014,7 @@ func TestUpdateMapContent(t *testing.T) {
 	assert.EqualValues(t, false, c2.IsMan)
 	assert.EqualValues(t, 2, c2.Gender)
 
-	cnt, err = testEngine.Table(testEngine.TableName(new(UpdateMapContent))).ID(c.Id).Update(map[string]interface{}{
+	cnt, err = testEngine.Table(new(UpdateMapContent)).ID(c.Id).Update(map[string]interface{}{
 		"age":    15,
 		"is_man": true,
 		"gender": 1,
@@ -1341,3 +1367,50 @@ func TestUpdateMultiplePK(t *testing.T) {
 	_, err = testEngine.ID(&MySlice{test.Id, test.Name}).Update(test)
 	assert.NoError(t, err)
 }
+
+type TestFieldType1 struct {
+	cb []byte
+}
+
+func (a *TestFieldType1) FromDB(src []byte) error {
+	a.cb = src
+	return nil
+}
+
+func (a TestFieldType1) ToDB() ([]byte, error) {
+	return a.cb, nil
+}
+
+type TestTable1 struct {
+	Id         int64
+	Field1     *TestFieldType1 `xorm:"text"`
+	UpdateTime time.Time
+}
+
+func TestNilFromDB(t *testing.T) {
+	assert.NoError(t, PrepareEngine())
+	assertSync(t, new(TestTable1))
+
+	cnt, err := testEngine.Insert(&TestTable1{
+		Field1: &TestFieldType1{
+			cb: []byte("string"),
+		},
+		UpdateTime: time.Now(),
+	})
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, cnt)
+
+	cnt, err = testEngine.Update(TestTable1{
+		UpdateTime: time.Now().Add(time.Second),
+	}, TestTable1{
+		Id: 1,
+	})
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, cnt)
+
+	cnt, err = testEngine.Insert(&TestTable1{
+		UpdateTime: time.Now(),
+	})
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, cnt)
+}
diff --git a/integrations/tags_test.go b/integrations/tags_test.go
index f787fffe..fc7b505e 100644
--- a/integrations/tags_test.go
+++ b/integrations/tags_test.go
@@ -757,6 +757,8 @@ func TestAutoIncrTag(t *testing.T) {
 	assert.True(t, cols[0].IsAutoIncrement)
 	assert.True(t, cols[0].IsPrimaryKey)
 	assert.Equal(t, "id", cols[0].Name)
+	assert.True(t, cols[0].DefaultIsEmpty)
+	assert.EqualValues(t, "", cols[0].Default)
 
 	type TestAutoIncr2 struct {
 		Id int64 `xorm:"id"`
@@ -770,6 +772,8 @@ func TestAutoIncrTag(t *testing.T) {
 	assert.False(t, cols[0].IsAutoIncrement)
 	assert.False(t, cols[0].IsPrimaryKey)
 	assert.Equal(t, "id", cols[0].Name)
+	assert.True(t, cols[0].DefaultIsEmpty)
+	assert.EqualValues(t, "", cols[0].Default)
 
 	type TestAutoIncr3 struct {
 		Id int64 `xorm:"'ID'"`
@@ -783,6 +787,8 @@ func TestAutoIncrTag(t *testing.T) {
 	assert.False(t, cols[0].IsAutoIncrement)
 	assert.False(t, cols[0].IsPrimaryKey)
 	assert.Equal(t, "ID", cols[0].Name)
+	assert.True(t, cols[0].DefaultIsEmpty)
+	assert.EqualValues(t, "", cols[0].Default)
 
 	type TestAutoIncr4 struct {
 		Id int64 `xorm:"pk"`
@@ -796,6 +802,8 @@ func TestAutoIncrTag(t *testing.T) {
 	assert.False(t, cols[0].IsAutoIncrement)
 	assert.True(t, cols[0].IsPrimaryKey)
 	assert.Equal(t, "id", cols[0].Name)
+	assert.True(t, cols[0].DefaultIsEmpty)
+	assert.EqualValues(t, "", cols[0].Default)
 }
 
 func TestTagComment(t *testing.T) {
@@ -809,6 +817,16 @@ func TestTagComment(t *testing.T) {
 		Id int64 `xorm:"comment(主键)"`
 	}
 
+	tb, err := testEngine.TableInfo(new(TestComment1))
+	assert.NoError(t, err)
+	cols := tb.Columns()
+	assert.EqualValues(t, 1, len(cols))
+	assert.False(t, cols[0].IsAutoIncrement)
+	assert.False(t, cols[0].IsPrimaryKey)
+	assert.Equal(t, "id", cols[0].Name)
+	assert.True(t, cols[0].DefaultIsEmpty)
+	assert.EqualValues(t, "", cols[0].Default)
+
 	assert.NoError(t, testEngine.Sync2(new(TestComment1)))
 
 	tables, err := testEngine.DBMetas()
@@ -823,6 +841,16 @@ func TestTagComment(t *testing.T) {
 		Id int64 `xorm:"comment('主键')"`
 	}
 
+	tb, err = testEngine.TableInfo(new(TestComment2))
+	assert.NoError(t, err)
+	cols = tb.Columns()
+	assert.EqualValues(t, 1, len(cols))
+	assert.False(t, cols[0].IsAutoIncrement)
+	assert.False(t, cols[0].IsPrimaryKey)
+	assert.Equal(t, "id", cols[0].Name)
+	assert.True(t, cols[0].DefaultIsEmpty)
+	assert.EqualValues(t, "", cols[0].Default)
+
 	assert.NoError(t, testEngine.Sync2(new(TestComment2)))
 
 	tables, err = testEngine.DBMetas()
@@ -841,6 +869,28 @@ func TestTagDefault(t *testing.T) {
 		Age  int `xorm:"default(10)"`
 	}
 
+	tb, err := testEngine.TableInfo(new(DefaultStruct))
+	assert.NoError(t, err)
+	cols := tb.Columns()
+	assert.EqualValues(t, 3, len(cols))
+	assert.True(t, cols[0].IsAutoIncrement)
+	assert.True(t, cols[0].IsPrimaryKey)
+	assert.Equal(t, "id", cols[0].Name)
+	assert.True(t, cols[0].DefaultIsEmpty)
+	assert.EqualValues(t, "", cols[0].Default)
+
+	assert.False(t, cols[1].IsAutoIncrement)
+	assert.False(t, cols[1].IsPrimaryKey)
+	assert.Equal(t, "name", cols[1].Name)
+	assert.True(t, cols[1].DefaultIsEmpty)
+	assert.EqualValues(t, "", cols[1].Default)
+
+	assert.False(t, cols[2].IsAutoIncrement)
+	assert.False(t, cols[2].IsPrimaryKey)
+	assert.Equal(t, "age", cols[2].Name)
+	assert.False(t, cols[2].DefaultIsEmpty)
+	assert.EqualValues(t, "10", cols[2].Default)
+
 	assertSync(t, new(DefaultStruct))
 
 	tables, err := testEngine.DBMetas()
@@ -880,10 +930,33 @@ func TestTagDefault2(t *testing.T) {
 	assert.NoError(t, PrepareEngine())
 
 	type DefaultStruct2 struct {
-		Id   int64
-		Name string
+		Id          int64
+		Name        string
+		NullDefault string `xorm:"default('NULL')"`
 	}
 
+	tb, err := testEngine.TableInfo(new(DefaultStruct2))
+	assert.NoError(t, err)
+	cols := tb.Columns()
+	assert.EqualValues(t, 3, len(cols))
+	assert.True(t, cols[0].IsAutoIncrement)
+	assert.True(t, cols[0].IsPrimaryKey)
+	assert.Equal(t, "id", cols[0].Name)
+	assert.True(t, cols[0].DefaultIsEmpty)
+	assert.EqualValues(t, "", cols[0].Default)
+
+	assert.False(t, cols[1].IsAutoIncrement)
+	assert.False(t, cols[1].IsPrimaryKey)
+	assert.Equal(t, "name", cols[1].Name)
+	assert.True(t, cols[1].DefaultIsEmpty)
+	assert.EqualValues(t, "", cols[1].Default)
+
+	assert.False(t, cols[2].IsAutoIncrement)
+	assert.False(t, cols[2].IsPrimaryKey)
+	assert.Equal(t, "null_default", cols[2].Name)
+	assert.False(t, cols[2].DefaultIsEmpty)
+	assert.EqualValues(t, "'NULL'", cols[2].Default)
+
 	assertSync(t, new(DefaultStruct2))
 
 	tables, err := testEngine.DBMetas()
diff --git a/integrations/testdata/import1.sql b/integrations/testdata/import1.sql
new file mode 100644
index 00000000..e004f41c
--- /dev/null
+++ b/integrations/testdata/import1.sql
@@ -0,0 +1,279 @@
+SET SQL_MODE = "NO_AUTO_VALUE_ON_ZERO";
+SET time_zone = "+00:00";
+
+-- 基本用户信息表
+CREATE TABLE IF NOT EXISTS `user` (
+  `id` int(11) NOT NULL AUTO_INCREMENT,
+  PRIMARY KEY (`id`),
+  KEY `uid` (`id`),
+  `user_name` varchar(128) CHARACTER SET utf8mb4 NOT NULL,
+  KEY `user_name` (`user_name`),
+  `email` varchar(32) NOT NULL,
+  KEY `email` (`email`),
+  `pass` varchar(256) NOT NULL,
+  `passwd` varchar(16) NOT NULL,
+  `uuid` TEXT NULL DEFAULT NULL COMMENT 'uuid',
+  `t` int(11) NOT NULL DEFAULT '0',
+  `u` bigint(20) NOT NULL,
+  `d` bigint(20) NOT NULL,
+  `plan` varchar(2) CHARACTER SET utf8mb4 NOT NULL DEFAULT 'A',
+  `node_group` INT NOT NULL DEFAULT '0',
+  `auto_reset_day` INT NOT NULL DEFAULT '0',
+  `auto_reset_bandwidth` DECIMAL(12,2) NOT NULL DEFAULT '0.00',
+  `transfer_enable` BIGINT(20) NOT NULL,
+  `port` int(11) NOT NULL,
+  `protocol_param` VARCHAR(128) NULL DEFAULT NULL,
+  `obfs_param` VARCHAR(128) NULL DEFAULT NULL,
+  `switch` tinyint(4) NOT NULL DEFAULT '1',
+  `enable` tinyint(4) NOT NULL DEFAULT '1',
+  `type` tinyint(4) NOT NULL DEFAULT '1',
+  `last_get_gift_time` int(11) NOT NULL DEFAULT '0',
+  `last_check_in_time` int(11) NOT NULL DEFAULT '0',
+  `last_rest_pass_time` int(11) NOT NULL DEFAULT '0',
+  `reg_date` datetime NOT NULL,
+  `invite_num` int(8) NOT NULL,
+  `money` decimal(12,2) NOT NULL,
+  `ref_by` int(11) NOT NULL DEFAULT '0',
+  `expire_time` int(11) NOT NULL DEFAULT '0',
+  `is_email_verify` tinyint(4) NOT NULL DEFAULT '0',
+  `reg_ip` varchar(128) NOT NULL DEFAULT '127.0.0.1',
+  `node_speedlimit` DECIMAL(12,2) NOT NULL DEFAULT '0.00',
+  `node_connector` int(11) NOT NULL DEFAULT '0',
+  `forbidden_ip` LONGTEXT NULL DEFAULT '',
+  `forbidden_port` LONGTEXT NULL DEFAULT '',
+  `disconnect_ip` LONGTEXT NULL DEFAULT '',
+  `is_hide` INT NOT NULL DEFAULT '0',
+  `last_detect_ban_time` datetime DEFAULT '1989-06-04 00:05:00',
+  `all_detect_number` int(11) NOT NULL DEFAULT '0',
+  `is_multi_user` INT NOT NULL DEFAULT '0',
+  `telegram_id` BIGINT NULL,
+  `is_admin` int(2) NOT NULL DEFAULT '0',
+  `im_type` int(11) DEFAULT '1',
+  `im_value` text,
+  `last_day_t` bigint(20) NOT NULL DEFAULT '0',
+  `mail_notified` int(11) NOT NULL DEFAULT '0',
+  `class` int(11) NOT NULL DEFAULT '0',
+  `class_expire` datetime NOT NULL DEFAULT '1989-06-04 00:05:00',
+  `expire_in` datetime NOT NULL DEFAULT '2099-06-04 00:05:00',
+  `theme` text NOT NULL,
+  `ga_token` text NOT NULL,
+  `ga_enable` int(11) NOT NULL DEFAULT '0',
+  `pac` LONGTEXT,
+  `remark` text
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+-- 用户流量信息表
+-- TODO: 重写流量信息提取逻辑
+CREATE TABLE IF NOT EXISTS `user_traffic_log` (
+  `id` int(11) NOT NULL AUTO_INCREMENT,
+  PRIMARY KEY (`id`),
+  `user_id` int(11) NOT NULL,
+  `u` BIGINT(20) NOT NULL,
+  `d` BIGINT(20) NOT NULL,
+  `node_id` int(11) NOT NULL,
+  `rate` float NOT NULL,
+  `traffic` varchar(32) NOT NULL,
+  `log_time` int(11) NOT NULL
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+-- 用户订阅 TOKEN 信息表
+CREATE TABLE IF NOT EXISTS `user_token` (
+  `id` int(11) NOT NULL AUTO_INCREMENT,
+  PRIMARY KEY (`id`),
+  `token` varchar(256) NOT NULL,
+  `user_id` int(11) NOT NULL,
+  `create_time` int(11) NOT NULL,
+  `expire_time` int(11) NOT NULL
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+-- 充值码使用信息表
+CREATE TABLE IF NOT EXISTS `charge_code` (
+  `id` bigint(20) NOT NULL AUTO_INCREMENT,
+  PRIMARY KEY (`id`),
+  `code` text NOT NULL,
+  `type` int(11) NOT NULL,
+  `number` DECIMAL(11,2) NOT NULL,
+  `isused` int(11) NOT NULL DEFAULT '0',
+  `userid` bigint(20) NOT NULL,
+  `usedatetime` datetime NOT NULL
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+-- 邀请码使用信息表
+CREATE TABLE IF NOT EXISTS `invite_code` (
+  `id` int(11) NOT NULL AUTO_INCREMENT,
+  PRIMARY KEY (`id`),
+  `code` varchar(128) NOT NULL,
+  KEY `user_id` (`user_id`),
+  `user_id` int(11) NOT NULL,
+  `created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  `updated_at` timestamp NOT NULL DEFAULT '2016-06-01 00:00:00'
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+-- 公告信息表
+CREATE TABLE IF NOT EXISTS `announcement` (
+  `id` int(11) NOT NULL AUTO_INCREMENT,
+  PRIMARY KEY (`id`),
+  `date` datetime NOT NULL,
+  `content` LONGTEXT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL,
+  `markdown` LONGTEXT NOT NULL
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+-- 节点信息表
+CREATE TABLE IF NOT EXISTS `node` (
+  `id` int(11) NOT NULL AUTO_INCREMENT,
+  PRIMARY KEY (`id`),
+  `name` varchar(128) NOT NULL,
+  `type` int(3) NOT NULL,
+  `online_user` int(11) NOT NULL,
+  `mu_only` INT NULL DEFAULT '0',
+  `online` BOOLEAN NOT NULL DEFAULT TRUE,
+  `server` varchar(128) NOT NULL,
+  `method` varchar(64) NOT NULL,
+  `info` varchar(128) NOT NULL,
+  `status` varchar(128) NOT NULL,
+  `node_group` INT NOT NULL DEFAULT '0',
+  `sort` int(3) NOT NULL,
+  `custom_method` tinyint(1) NOT NULL DEFAULT '0',
+  `traffic_rate` float NOT NULL DEFAULT '1',
+  `node_class` int(11) NOT NULL DEFAULT '0',
+  `node_speedlimit` DECIMAL(12,2) NOT NULL DEFAULT '0.00',
+  `node_connector` int(11) NOT NULL DEFAULT '0',
+  `node_bandwidth` bigint(20) NOT NULL DEFAULT '0',
+  `node_bandwidth_limit` bigint(20) NOT NULL DEFAULT '0',
+  `bandwidthlimit_resetday` int(11) NOT NULL DEFAULT '0',
+  `node_heartbeat` bigint(20) NOT NULL DEFAULT '0',
+  `node_ip` text
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+-- TODO: 修改 VPN 节点的结算说明
+
+-- 商店数据表
+CREATE TABLE `shop` (
+  `id` BIGINT NOT NULL AUTO_INCREMENT,
+  `name` TEXT NOT NULL,
+  `price` DECIMAL(12,2) NOT NULL,
+  `content` TEXT NOT NULL,
+  `auto_renew` INT NOT NULL,
+  `status` INT NOT NULL DEFAULT '1',
+  `auto_reset_bandwidth` INT NOT NULL DEFAULT '0',
+  PRIMARY KEY (`id`)
+) ENGINE = InnoDB CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+-- 优惠券数据表
+CREATE TABLE `coupon` (
+  `id` BIGINT NOT NULL AUTO_INCREMENT,
+  `code` TEXT NOT NULL,
+  `onetime` INT NOT NULL,
+  `expire` BIGINT NOT NULL,
+  `shop` TEXT NOT NULL,
+  `credit` INT NOT NULL,
+  PRIMARY KEY (`id`)
+) ENGINE = InnoDB CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+-- 购买记录数据表
+CREATE TABLE `bought` (
+  `id` BIGINT NOT NULL AUTO_INCREMENT,
+  `userid` BIGINT NOT NULL,
+  `shopid` BIGINT NOT NULL,
+  `coupon` TEXT NOT NULL,
+  `datetime` BIGINT NOT NULL,
+  `renew` BIGINT(11) NOT NULL,
+  `price` DECIMAL(12,2) NOT NULL,
+  PRIMARY KEY (`id`)
+) ENGINE = InnoDB CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+-- 工单数据表
+CREATE TABLE `ticket` (
+  `id` BIGINT NOT NULL AUTO_INCREMENT,
+  `title` LONGTEXT NOT NULL,
+  `status` INT NOT NULL DEFAULT '1',
+  `content` LONGTEXT NOT NULL,
+  `rootid` BIGINT NOT NULL,`userid` BIGINT NOT NULL,
+  `datetime` BIGINT NOT NULL,
+  PRIMARY KEY (`id`)
+) ENGINE = InnoDB CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+-- 返利记录数据表
+CREATE TABLE `payback` (
+  `id` BIGINT NOT NULL AUTO_INCREMENT,
+  `total` DECIMAL(12,2) NOT NULL,
+  `userid` BIGINT NOT NULL,
+  `ref_by` BIGINT NOT NULL,
+  `ref_get` DECIMAL(12,2) NOT NULL,
+  `datetime` BIGINT NOT NULL,
+  PRIMARY KEY (`id`)
+) ENGINE = InnoDB CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+-- 审计规则数据表
+CREATE TABLE `detect_list` (
+  `id` BIGINT NOT NULL AUTO_INCREMENT,
+  `name` LONGTEXT NOT NULL,
+  `type` INT NOT NULL,
+  `text` LONGTEXT NOT NULL,
+  `regex` LONGTEXT NOT NULL,
+  PRIMARY KEY (`id`)
+) ENGINE = InnoDB CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+-- 审计记录数据表
+CREATE TABLE `detect_log` (
+  `id` BIGINT NOT NULL AUTO_INCREMENT,
+  `user_id` BIGINT NOT NULL,
+  `node_id` INT NOT NULL,
+  `list_id` BIGINT NOT NULL,
+  `datetime` BIGINT NOT NULL,
+  PRIMARY KEY (`id`)
+) ENGINE = InnoDB CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+-- 中转规则数据表
+CREATE TABLE IF NOT EXISTS `relay` (
+  `id` bigint(20) NOT NULL AUTO_INCREMENT,
+  PRIMARY KEY (`id`),
+  `user_id` bigint(20) NOT NULL,
+  `source_node_id` bigint(20) NOT NULL,
+  `dist_node_id` bigint(20) NOT NULL,
+  `dist_ip` text NOT NULL,
+  `port` int(11) NOT NULL,
+  `priority` int(11) NOT NULL
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+-- 用户订阅日志
+CREATE TABLE IF NOT EXISTS `user_subscribe_log` (
+  `id`                 int(11) unsigned NOT NULL AUTO_INCREMENT,
+  `user_name`          varchar(128)     NOT NULL COMMENT '用户名',
+  `user_id`            int(11)          NOT NULL COMMENT '用户 ID',
+  `email`              varchar(32)      NOT NULL COMMENT '用户邮箱',
+  `subscribe_type`     varchar(20)      NOT NULL COMMENT '获取的订阅类型',
+  `request_ip`         varchar(128)     NOT NULL COMMENT '请求 IP',
+  `request_time`       datetime         NOT NULL COMMENT '请求时间',
+  `request_user_agent` text                      COMMENT '请求 UA 信息',
+  PRIMARY KEY (`id`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='用户订阅日志';
+
+-- 审计封禁日志
+CREATE TABLE IF NOT EXISTS `detect_ban_log` (
+  `id`                int(11) unsigned NOT NULL AUTO_INCREMENT,
+  `user_name`         varchar(128)     NOT NULL COMMENT '用户名',
+  `user_id`           int(11)          NOT NULL COMMENT '用户 ID',
+  `email`             varchar(32)      NOT NULL COMMENT '用户邮箱',
+  `detect_number`     int(11)          NOT NULL COMMENT '本次违规次数',
+  `ban_time`          int(11)          NOT NULL COMMENT '本次封禁时长',
+  `start_time`        bigint(20)       NOT NULL COMMENT '统计开始时间',
+  `end_time`          bigint(20)       NOT NULL COMMENT '统计结束时间',
+  `all_detect_number` int(11)          NOT NULL COMMENT '累计违规次数',
+  PRIMARY KEY (`id`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='审计封禁日志';
+
+-- 管理员操作记录
+CREATE TABLE IF NOT EXISTS `gconfig` (
+  `id`             int(11) unsigned NOT NULL AUTO_INCREMENT,
+  `key`            varchar(128)     NOT NULL COMMENT '配置键名',
+  `type`           varchar(32)      NOT NULL COMMENT '值类型',
+  `value`          text             NOT NULL COMMENT '配置值',
+  `oldvalue`       text             NOT NULL COMMENT '之前的配置值',
+  `name`           varchar(128)     NOT NULL COMMENT '配置名称',
+  `comment`        text             NOT NULL COMMENT '配置描述',
+  `operator_id`    int(11)          NOT NULL COMMENT '操作员 ID',
+  `operator_name`  varchar(128)     NOT NULL COMMENT '操作员名称',
+  `operator_email` varchar(32)      NOT NULL COMMENT '操作员邮箱',
+  `last_update`    bigint(20)       NOT NULL COMMENT '修改时间',
+  PRIMARY KEY (`id`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='网站配置';
\ No newline at end of file
diff --git a/integrations/tests.go b/integrations/tests.go
index c8219935..8b14b0f4 100644
--- a/integrations/tests.go
+++ b/integrations/tests.go
@@ -8,6 +8,7 @@ import (
 	"database/sql"
 	"flag"
 	"fmt"
+	"net/url"
 	"os"
 	"strings"
 	"testing"
@@ -35,7 +36,10 @@ var (
 	schema             = flag.String("schema", "", "specify the schema")
 	ignoreSelectUpdate = flag.Bool("ignore_select_update", false, "ignore select update if implementation difference, only for tidb")
 	ingoreUpdateLimit  = flag.Bool("ignore_update_limit", false, "ignore update limit if implementation difference, only for cockroach")
+	doNVarcharTest     = flag.Bool("do_nvarchar_override_test", false, "do nvarchar override test in sync table, only for mssql")
 	quotePolicyStr     = flag.String("quote", "always", "quote could be always, none, reversed")
+	defaultVarchar     = flag.String("default_varchar", "varchar", "default varchar type, mssql only, could be varchar or nvarchar, default is varchar")
+	defaultChar        = flag.String("default_char", "char", "default char type, mssql only, could be char or nchar, default is char")
 	tableMapper        names.Mapper
 	colMapper          names.Mapper
 )
@@ -94,6 +98,13 @@ func createEngine(dbType, connStr string) error {
 					return fmt.Errorf("db.Exec: %v", err)
 				}
 				db.Close()
+			case schemas.SQLITE, "sqlite":
+				u, err := url.Parse(connStr)
+				if err != nil {
+					return err
+				}
+				connStr = u.Path
+				*ignoreSelectUpdate = true
 			default:
 				*ignoreSelectUpdate = true
 			}
@@ -137,6 +148,11 @@ func createEngine(dbType, connStr string) error {
 		} else {
 			testEngine.SetQuotePolicy(dialects.QuotePolicyAlways)
 		}
+
+		testEngine.Dialect().SetParams(map[string]string{
+			"DEFAULT_VARCHAR": *defaultVarchar,
+			"DEFAULT_CHAR":    *defaultChar,
+		})
 	}
 
 	tableMapper = testEngine.GetTableMapper()
@@ -150,23 +166,28 @@ func createEngine(dbType, connStr string) error {
 	for _, table := range tables {
 		tableNames = append(tableNames, table.Name)
 	}
-	if err = testEngine.DropTables(tableNames...); err != nil {
-		return err
-	}
-	return nil
+	return testEngine.DropTables(tableNames...)
 }
 
+// PrepareEngine prepare tests ORM engine
 func PrepareEngine() error {
 	return createEngine(dbType, connString)
 }
 
+// MainTest the tests entrance
 func MainTest(m *testing.M) {
 	flag.Parse()
 
 	dbType = *db
 	if *db == "sqlite3" {
 		if ptrConnStr == nil {
-			connString = "./test.db?cache=shared&mode=rwc"
+			connString = "./test_sqlite3.db?cache=shared&mode=rwc"
+		} else {
+			connString = *ptrConnStr
+		}
+	} else if *db == "sqlite" {
+		if ptrConnStr == nil {
+			connString = "./test_sqlite.db?cache=shared&mode=rwc"
 		} else {
 			connString = *ptrConnStr
 		}
diff --git a/integrations/types_test.go b/integrations/types_test.go
index 112308f3..d0357d6b 100644
--- a/integrations/types_test.go
+++ b/integrations/types_test.go
@@ -375,3 +375,30 @@ func TestCustomType2(t *testing.T) {
 
 	fmt.Println(users)
 }
+
+func TestUnsigned(t *testing.T) {
+	type MyUnsignedStruct struct {
+		Id uint64
+	}
+
+	assert.NoError(t, PrepareEngine())
+	assertSync(t, new(MyUnsignedStruct))
+
+	tables, err := testEngine.DBMetas()
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, len(tables))
+	assert.EqualValues(t, 1, len(tables[0].Columns()))
+
+	switch testEngine.Dialect().URI().DBType {
+	case schemas.SQLITE:
+		assert.EqualValues(t, "INTEGER", tables[0].Columns()[0].SQLType.Name)
+	case schemas.MYSQL:
+		assert.EqualValues(t, "UNSIGNED BIGINT", tables[0].Columns()[0].SQLType.Name)
+	case schemas.POSTGRES:
+		assert.EqualValues(t, "BIGINT", tables[0].Columns()[0].SQLType.Name)
+	case schemas.MSSQL:
+		assert.EqualValues(t, "BIGINT", tables[0].Columns()[0].SQLType.Name)
+	default:
+		assert.False(t, true, "Unsigned is not implemented")
+	}
+}
diff --git a/interface.go b/interface.go
index 6aac4ae8..55162c8c 100644
--- a/interface.go
+++ b/interface.go
@@ -101,6 +101,7 @@ type EngineInterface interface {
 	SetCacher(string, caches.Cacher)
 	SetConnMaxLifetime(time.Duration)
 	SetColumnMapper(names.Mapper)
+	SetTagIdentifier(string)
 	SetDefaultCacher(caches.Cacher)
 	SetLogger(logger interface{})
 	SetLogLevel(log.LogLevel)
@@ -120,6 +121,7 @@ type EngineInterface interface {
 	TableInfo(bean interface{}) (*schemas.Table, error)
 	TableName(interface{}, ...bool) string
 	UnMapType(reflect.Type)
+	EnableSessionID(bool)
 }
 
 var (
diff --git a/internal/json/json.go b/internal/json/json.go
index c9a2eb4e..ef52f51f 100644
--- a/internal/json/json.go
+++ b/internal/json/json.go
@@ -6,15 +6,15 @@ package json
 
 import "encoding/json"
 
-// JSONInterface represents an interface to handle json data
-type JSONInterface interface {
+// Interface represents an interface to handle json data
+type Interface interface {
 	Marshal(v interface{}) ([]byte, error)
 	Unmarshal(data []byte, v interface{}) error
 }
 
 var (
 	// DefaultJSONHandler default json handler
-	DefaultJSONHandler JSONInterface = StdJSON{}
+	DefaultJSONHandler Interface = StdJSON{}
 )
 
 // StdJSON implements JSONInterface via encoding/json
diff --git a/internal/json/jsoniter.go b/internal/json/jsoniter.go
new file mode 100644
index 00000000..cfe7a19e
--- /dev/null
+++ b/internal/json/jsoniter.go
@@ -0,0 +1,28 @@
+// Copyright 2021 The Xorm Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build jsoniter
+
+package json
+
+import (
+	jsoniter "github.com/json-iterator/go"
+)
+
+func init() {
+	DefaultJSONHandler = JSONiter{}
+}
+
+// JSONiter implements JSONInterface via jsoniter
+type JSONiter struct{}
+
+// Marshal implements JSONInterface
+func (JSONiter) Marshal(v interface{}) ([]byte, error) {
+	return jsoniter.Marshal(v)
+}
+
+// Unmarshal implements JSONInterface
+func (JSONiter) Unmarshal(data []byte, v interface{}) error {
+	return jsoniter.Unmarshal(data, v)
+}
diff --git a/internal/statements/cache.go b/internal/statements/cache.go
index cb33df08..669cd018 100644
--- a/internal/statements/cache.go
+++ b/internal/statements/cache.go
@@ -12,6 +12,7 @@ import (
 	"xorm.io/xorm/schemas"
 )
 
+// ConvertIDSQL converts SQL with id
 func (statement *Statement) ConvertIDSQL(sqlStr string) string {
 	if statement.RefTable != nil {
 		cols := statement.RefTable.PKColumns()
@@ -37,6 +38,7 @@ func (statement *Statement) ConvertIDSQL(sqlStr string) string {
 	return ""
 }
 
+// ConvertUpdateSQL converts update SQL
 func (statement *Statement) ConvertUpdateSQL(sqlStr string) (string, string) {
 	if statement.RefTable == nil || len(statement.RefTable.PrimaryKeys) != 1 {
 		return "", ""
diff --git a/internal/statements/expr_param.go b/internal/statements/expr_param.go
index 6657408e..d0c355d3 100644
--- a/internal/statements/expr_param.go
+++ b/internal/statements/expr_param.go
@@ -12,6 +12,7 @@ import (
 	"xorm.io/xorm/schemas"
 )
 
+// ErrUnsupportedExprType represents an error with unsupported express type
 type ErrUnsupportedExprType struct {
 	tp string
 }
diff --git a/internal/statements/pk.go b/internal/statements/pk.go
index d0787719..59da89c0 100644
--- a/internal/statements/pk.go
+++ b/internal/statements/pk.go
@@ -20,6 +20,21 @@ var (
 	uintType   = reflect.TypeOf(uint64(0))
 )
 
+// ErrIDConditionWithNoTable represents an error there is no reference table with an ID condition
+type ErrIDConditionWithNoTable struct {
+	ID schemas.PK
+}
+
+func (err ErrIDConditionWithNoTable) Error() string {
+	return fmt.Sprintf("ID condition %#v need reference table", err.ID)
+}
+
+// IsIDConditionWithNoTableErr return true if the err is ErrIDConditionWithNoTable
+func IsIDConditionWithNoTableErr(err error) bool {
+	_, ok := err.(ErrIDConditionWithNoTable)
+	return ok
+}
+
 // ID generate "where id = ? " statement or for composite key "where key1 = ? and key2 = ?"
 func (statement *Statement) ID(id interface{}) *Statement {
 	switch t := id.(type) {
@@ -58,11 +73,16 @@ func (statement *Statement) ID(id interface{}) *Statement {
 	return statement
 }
 
+// ProcessIDParam handles the process of id condition
 func (statement *Statement) ProcessIDParam() error {
-	if statement.idParam == nil || statement.RefTable == nil {
+	if statement.idParam == nil {
 		return nil
 	}
 
+	if statement.RefTable == nil {
+		return ErrIDConditionWithNoTable{statement.idParam}
+	}
+
 	if len(statement.RefTable.PrimaryKeys) != len(statement.idParam) {
 		return fmt.Errorf("ID condition is error, expect %d primarykeys, there are %d",
 			len(statement.RefTable.PrimaryKeys),
diff --git a/internal/statements/query.go b/internal/statements/query.go
index ab3021bf..f1b36770 100644
--- a/internal/statements/query.go
+++ b/internal/statements/query.go
@@ -14,6 +14,7 @@ import (
 	"xorm.io/xorm/schemas"
 )
 
+// GenQuerySQL generate query SQL
 func (statement *Statement) GenQuerySQL(sqlOrArgs ...interface{}) (string, []interface{}, error) {
 	if len(sqlOrArgs) > 0 {
 		return statement.ConvertSQLOrArgs(sqlOrArgs...)
@@ -72,6 +73,7 @@ func (statement *Statement) GenQuerySQL(sqlOrArgs ...interface{}) (string, []int
 	return sqlStr, args, nil
 }
 
+// GenSumSQL generates sum SQL
 func (statement *Statement) GenSumSQL(bean interface{}, columns ...string) (string, []interface{}, error) {
 	if statement.RawSQL != "" {
 		return statement.GenRawSQL(), statement.RawParams, nil
@@ -102,6 +104,7 @@ func (statement *Statement) GenSumSQL(bean interface{}, columns ...string) (stri
 	return sqlStr, append(statement.joinArgs, condArgs...), nil
 }
 
+// GenGetSQL generates Get SQL
 func (statement *Statement) GenGetSQL(bean interface{}) (string, []interface{}, error) {
 	v := rValue(bean)
 	isStruct := v.Kind() == reflect.Struct
@@ -316,6 +319,7 @@ func (statement *Statement) genSelectSQL(columnStr string, needLimit, needOrderB
 	return buf.String(), condArgs, nil
 }
 
+// GenExistSQL generates Exist SQL
 func (statement *Statement) GenExistSQL(bean ...interface{}) (string, []interface{}, error) {
 	if statement.RawSQL != "" {
 		return statement.GenRawSQL(), statement.RawParams, nil
@@ -385,6 +389,7 @@ func (statement *Statement) GenExistSQL(bean ...interface{}) (string, []interfac
 	return sqlStr, args, nil
 }
 
+// GenFindSQL generates Find SQL
 func (statement *Statement) GenFindSQL(autoCond builder.Cond) (string, []interface{}, error) {
 	if statement.RawSQL != "" {
 		return statement.GenRawSQL(), statement.RawParams, nil
diff --git a/internal/statements/statement.go b/internal/statements/statement.go
index ed7bdaeb..3dd036a6 100644
--- a/internal/statements/statement.go
+++ b/internal/statements/statement.go
@@ -90,19 +90,17 @@ func NewStatement(dialect dialects.Dialect, tagParser *tags.Parser, defaultTimeZ
 	return statement
 }
 
+// SetTableName set table name
 func (statement *Statement) SetTableName(tableName string) {
 	statement.tableName = tableName
 }
 
-func (statement *Statement) omitStr() string {
-	return statement.dialect.Quoter().Join(statement.OmitColumnMap, " ,")
-}
-
 // GenRawSQL generates correct raw sql
 func (statement *Statement) GenRawSQL() string {
 	return statement.ReplaceQuote(statement.RawSQL)
 }
 
+// GenCondSQL generates condition SQL
 func (statement *Statement) GenCondSQL(condOrBuilder interface{}) (string, []interface{}, error) {
 	condSQL, condArgs, err := builder.ToSQL(condOrBuilder)
 	if err != nil {
@@ -111,6 +109,7 @@ func (statement *Statement) GenCondSQL(condOrBuilder interface{}) (string, []int
 	return statement.ReplaceQuote(condSQL), condArgs, nil
 }
 
+// ReplaceQuote replace sql key words with quote
 func (statement *Statement) ReplaceQuote(sql string) string {
 	if sql == "" || statement.dialect.URI().DBType == schemas.MYSQL ||
 		statement.dialect.URI().DBType == schemas.SQLITE {
@@ -119,11 +118,12 @@ func (statement *Statement) ReplaceQuote(sql string) string {
 	return statement.dialect.Quoter().Replace(sql)
 }
 
+// SetContextCache sets context cache
 func (statement *Statement) SetContextCache(ctxCache contexts.ContextCache) {
 	statement.Context = ctxCache
 }
 
-// Init reset all the statement's fields
+// Reset reset all the statement's fields
 func (statement *Statement) Reset() {
 	statement.RefTable = nil
 	statement.Start = 0
@@ -163,7 +163,7 @@ func (statement *Statement) Reset() {
 	statement.LastError = nil
 }
 
-// NoAutoCondition if you do not want convert bean's field as query condition, then use this function
+// SetNoAutoCondition if you do not want convert bean's field as query condition, then use this function
 func (statement *Statement) SetNoAutoCondition(no ...bool) *Statement {
 	statement.NoAutoCondition = true
 	if len(no) > 0 {
@@ -271,6 +271,7 @@ func (statement *Statement) NotIn(column string, args ...interface{}) *Statement
 	return statement
 }
 
+// SetRefValue set ref value
 func (statement *Statement) SetRefValue(v reflect.Value) error {
 	var err error
 	statement.RefTable, err = statement.tagParser.ParseWithCache(reflect.Indirect(v))
@@ -285,6 +286,7 @@ func rValue(bean interface{}) reflect.Value {
 	return reflect.Indirect(reflect.ValueOf(bean))
 }
 
+// SetRefBean set ref bean
 func (statement *Statement) SetRefBean(bean interface{}) error {
 	var err error
 	statement.RefTable, err = statement.tagParser.ParseWithCache(rValue(bean))
@@ -390,6 +392,7 @@ func (statement *Statement) Cols(columns ...string) *Statement {
 	return statement
 }
 
+// ColumnStr returns column string
 func (statement *Statement) ColumnStr() string {
 	return statement.dialect.Quoter().Join(statement.ColumnMap, ", ")
 }
@@ -493,11 +496,12 @@ func (statement *Statement) Asc(colNames ...string) *Statement {
 	return statement
 }
 
+// Conds returns condtions
 func (statement *Statement) Conds() builder.Cond {
 	return statement.cond
 }
 
-// Table tempororily set table name, the parameter could be a string or a pointer of struct
+// SetTable tempororily set table name, the parameter could be a string or a pointer of struct
 func (statement *Statement) SetTable(tableNameOrBean interface{}) error {
 	v := rValue(tableNameOrBean)
 	t := v.Type()
@@ -564,7 +568,7 @@ func (statement *Statement) Join(joinOP string, tablename interface{}, condition
 	return statement
 }
 
-// tbName get some table's table name
+// tbNameNoSchema get some table's table name
 func (statement *Statement) tbNameNoSchema(table *schemas.Table) string {
 	if len(statement.AltTableName) > 0 {
 		return statement.AltTableName
@@ -585,12 +589,13 @@ func (statement *Statement) Having(conditions string) *Statement {
 	return statement
 }
 
-// Unscoped always disable struct tag "deleted"
+// SetUnscoped always disable struct tag "deleted"
 func (statement *Statement) SetUnscoped() *Statement {
 	statement.unscoped = true
 	return statement
 }
 
+// GetUnscoped return true if it's unscoped
 func (statement *Statement) GetUnscoped() bool {
 	return statement.unscoped
 }
@@ -636,6 +641,7 @@ func (statement *Statement) genColumnStr() string {
 	return buf.String()
 }
 
+// GenCreateTableSQL generated create table SQL
 func (statement *Statement) GenCreateTableSQL() []string {
 	statement.RefTable.StoreEngine = statement.StoreEngine
 	statement.RefTable.Charset = statement.Charset
@@ -643,6 +649,7 @@ func (statement *Statement) GenCreateTableSQL() []string {
 	return s
 }
 
+// GenIndexSQL generated create index SQL
 func (statement *Statement) GenIndexSQL() []string {
 	var sqls []string
 	tbName := statement.TableName()
@@ -659,6 +666,7 @@ func uniqueName(tableName, uqeName string) string {
 	return fmt.Sprintf("UQE_%v_%v", tableName, uqeName)
 }
 
+// GenUniqueSQL generates unique SQL
 func (statement *Statement) GenUniqueSQL() []string {
 	var sqls []string
 	tbName := statement.TableName()
@@ -671,6 +679,7 @@ func (statement *Statement) GenUniqueSQL() []string {
 	return sqls
 }
 
+// GenDelIndexSQL generate delete index SQL
 func (statement *Statement) GenDelIndexSQL() []string {
 	var sqls []string
 	tbName := statement.TableName()
@@ -704,7 +713,7 @@ func (statement *Statement) buildConds2(table *schemas.Table, bean interface{},
 			col.SQLType.IsBlob() || col.SQLType.Name == schemas.TimeStampz) {
 			continue
 		}
-		if col.SQLType.IsJson() {
+		if col.IsJSON {
 			continue
 		}
 
@@ -813,7 +822,7 @@ func (statement *Statement) buildConds2(table *schemas.Table, bean interface{},
 					continue
 				}
 			} else {
-				if col.SQLType.IsJson() {
+				if col.IsJSON {
 					if col.SQLType.IsText() {
 						bytes, err := json.DefaultJSONHandler.Marshal(fieldValue.Interface())
 						if err != nil {
@@ -896,6 +905,7 @@ func (statement *Statement) buildConds2(table *schemas.Table, bean interface{},
 	return builder.And(conds...), nil
 }
 
+// BuildConds builds condition
 func (statement *Statement) BuildConds(table *schemas.Table, bean interface{}, includeVersion bool, includeUpdated bool, includeNil bool, includeAutoIncr bool, addedTableName bool) (builder.Cond, error) {
 	return statement.buildConds2(table, bean, includeVersion, includeUpdated, includeNil, includeAutoIncr, statement.allUseBool, statement.useAllCols,
 		statement.unscoped, statement.MustColumnMap, statement.TableName(), statement.TableAlias, addedTableName)
@@ -911,12 +921,10 @@ func (statement *Statement) mergeConds(bean interface{}) error {
 		statement.cond = statement.cond.And(autoCond)
 	}
 
-	if err := statement.ProcessIDParam(); err != nil {
-		return err
-	}
-	return nil
+	return statement.ProcessIDParam()
 }
 
+// GenConds generates conditions
 func (statement *Statement) GenConds(bean interface{}) (string, []interface{}, error) {
 	if err := statement.mergeConds(bean); err != nil {
 		return "", nil, err
@@ -930,6 +938,7 @@ func (statement *Statement) quoteColumnStr(columnStr string) string {
 	return statement.dialect.Quoter().Join(columns, ",")
 }
 
+// ConvertSQLOrArgs converts sql or args
 func (statement *Statement) ConvertSQLOrArgs(sqlOrArgs ...interface{}) (string, []interface{}, error) {
 	sql, args, err := convertSQLOrArgs(sqlOrArgs...)
 	if err != nil {
diff --git a/internal/statements/statement_args.go b/internal/statements/statement_args.go
index dc14467d..64089c1e 100644
--- a/internal/statements/statement_args.go
+++ b/internal/statements/statement_args.go
@@ -77,6 +77,7 @@ func convertArg(arg interface{}, convertFunc func(string) string) string {
 
 const insertSelectPlaceHolder = true
 
+// WriteArg writes an arg
 func (statement *Statement) WriteArg(w *builder.BytesWriter, arg interface{}) error {
 	switch argv := arg.(type) {
 	case *builder.Builder:
@@ -116,6 +117,7 @@ func (statement *Statement) WriteArg(w *builder.BytesWriter, arg interface{}) er
 	return nil
 }
 
+// WriteArgs writes args
 func (statement *Statement) WriteArgs(w *builder.BytesWriter, args []interface{}) error {
 	for i, arg := range args {
 		if err := statement.WriteArg(w, arg); err != nil {
diff --git a/internal/statements/update.go b/internal/statements/update.go
index b6ae118e..251880b2 100644
--- a/internal/statements/update.go
+++ b/internal/statements/update.go
@@ -130,7 +130,7 @@ func (statement *Statement) BuildUpdates(tableValue reflect.Value,
 			}
 		}
 
-		if structConvert, ok := fieldValue.Interface().(convert.Conversion); ok {
+		if structConvert, ok := fieldValue.Interface().(convert.Conversion); ok && !fieldValue.IsNil() {
 			data, err := structConvert.ToDB()
 			if err != nil {
 				return nil, nil, err
@@ -204,7 +204,7 @@ func (statement *Statement) BuildUpdates(tableValue reflect.Value,
 					continue
 				}
 			} else {
-				if !col.SQLType.IsJson() {
+				if !col.IsJSON {
 					table, err := statement.tagParser.ParseWithCache(fieldValue)
 					if err != nil {
 						val = fieldValue.Interface()
diff --git a/internal/statements/values.go b/internal/statements/values.go
index a1102c54..71327c55 100644
--- a/internal/statements/values.go
+++ b/internal/statements/values.go
@@ -36,18 +36,21 @@ func (statement *Statement) Value2Interface(col *schemas.Column, fieldValue refl
 		}
 	}
 
-	if fieldConvert, ok := fieldValue.Interface().(convert.Conversion); ok {
-		data, err := fieldConvert.ToDB()
-		if err != nil {
-			return nil, err
+	isNil := fieldValue.Kind() == reflect.Ptr && fieldValue.IsNil()
+	if !isNil {
+		if fieldConvert, ok := fieldValue.Interface().(convert.Conversion); ok {
+			data, err := fieldConvert.ToDB()
+			if err != nil {
+				return nil, err
+			}
+			if col.SQLType.IsBlob() {
+				return data, nil
+			}
+			if nil == data {
+				return nil, nil
+			}
+			return string(data), nil
 		}
-		if col.SQLType.IsBlob() {
-			return data, nil
-		}
-		if nil == data {
-			return nil, nil
-		}
-		return string(data), nil
 	}
 
 	fieldType := fieldValue.Type()
@@ -83,7 +86,7 @@ func (statement *Statement) Value2Interface(col *schemas.Column, fieldValue refl
 			return t.Float64, nil
 		}
 
-		if !col.SQLType.IsJson() {
+		if !col.IsJSON {
 			// !<winxxp>! 增加支持driver.Valuer接口的结构，如sql.NullString
 			if v, ok := fieldValue.Interface().(driver.Valuer); ok {
 				return v.Value()
diff --git a/internal/utils/name.go b/internal/utils/name.go
index f5fc3ff7..840dd9e8 100644
--- a/internal/utils/name.go
+++ b/internal/utils/name.go
@@ -8,6 +8,7 @@ import (
 	"fmt"
 )
 
+// IndexName returns index name
 func IndexName(tableName, idxName string) string {
 	return fmt.Sprintf("IDX_%v_%v", tableName, idxName)
 }
diff --git a/internal/utils/reflect.go b/internal/utils/reflect.go
index 3dad6bfe..7973d4d3 100644
--- a/internal/utils/reflect.go
+++ b/internal/utils/reflect.go
@@ -8,6 +8,7 @@ import (
 	"reflect"
 )
 
+// ReflectValue returns value of a bean
 func ReflectValue(bean interface{}) reflect.Value {
 	return reflect.Indirect(reflect.ValueOf(bean))
 }
diff --git a/internal/utils/sql.go b/internal/utils/sql.go
index 5e68c4a4..369ca2b8 100644
--- a/internal/utils/sql.go
+++ b/internal/utils/sql.go
@@ -8,6 +8,7 @@ import (
 	"strings"
 )
 
+// IsSubQuery returns true if it contains a sub query
 func IsSubQuery(tbName string) bool {
 	const selStr = "select"
 	if len(tbName) <= len(selStr)+1 {
diff --git a/internal/utils/strings.go b/internal/utils/strings.go
index b5dc37b7..86469c0f 100644
--- a/internal/utils/strings.go
+++ b/internal/utils/strings.go
@@ -8,10 +8,12 @@ import (
 	"strings"
 )
 
+// IndexNoCase index a string in a string with no care of capitalize
 func IndexNoCase(s, sep string) int {
 	return strings.Index(strings.ToLower(s), strings.ToLower(sep))
 }
 
+// SplitNoCase split a string by a seperator with no care of capitalize
 func SplitNoCase(s, sep string) []string {
 	idx := IndexNoCase(s, sep)
 	if idx < 0 {
@@ -20,6 +22,7 @@ func SplitNoCase(s, sep string) []string {
 	return strings.Split(s, s[idx:idx+len(sep)])
 }
 
+// SplitNNoCase split n by a seperator with no care of capitalize
 func SplitNNoCase(s, sep string, n int) []string {
 	idx := IndexNoCase(s, sep)
 	if idx < 0 {
@@ -27,4 +30,3 @@ func SplitNNoCase(s, sep string, n int) []string {
 	}
 	return strings.SplitN(s, s[idx:idx+len(sep)], n)
 }
-
diff --git a/internal/utils/zero.go b/internal/utils/zero.go
index 8f033c60..007e3c33 100644
--- a/internal/utils/zero.go
+++ b/internal/utils/zero.go
@@ -9,6 +9,7 @@ import (
 	"time"
 )
 
+// Zeroable represents an interface which could know if it's a zero value
 type Zeroable interface {
 	IsZero() bool
 }
@@ -21,39 +22,39 @@ func IsZero(k interface{}) bool {
 		return true
 	}
 
-	switch k.(type) {
+	switch t := k.(type) {
 	case int:
-		return k.(int) == 0
+		return t == 0
 	case int8:
-		return k.(int8) == 0
+		return t == 0
 	case int16:
-		return k.(int16) == 0
+		return t == 0
 	case int32:
-		return k.(int32) == 0
+		return t == 0
 	case int64:
-		return k.(int64) == 0
+		return t == 0
 	case uint:
-		return k.(uint) == 0
+		return t == 0
 	case uint8:
-		return k.(uint8) == 0
+		return t == 0
 	case uint16:
-		return k.(uint16) == 0
+		return t == 0
 	case uint32:
-		return k.(uint32) == 0
+		return t == 0
 	case uint64:
-		return k.(uint64) == 0
+		return t == 0
 	case float32:
-		return k.(float32) == 0
+		return t == 0
 	case float64:
-		return k.(float64) == 0
+		return t == 0
 	case bool:
-		return k.(bool) == false
+		return !t
 	case string:
-		return k.(string) == ""
+		return t == ""
 	case *time.Time:
-		return k.(*time.Time) == nilTime || IsTimeZero(*k.(*time.Time))
+		return t == nilTime || IsTimeZero(*t)
 	case time.Time:
-		return IsTimeZero(k.(time.Time))
+		return IsTimeZero(t)
 	case Zeroable:
 		return k.(Zeroable) == nil || k.(Zeroable).IsZero()
 	case reflect.Value: // for go version less than 1.13 because reflect.Value has no method IsZero
@@ -65,6 +66,7 @@ func IsZero(k interface{}) bool {
 
 var zeroType = reflect.TypeOf((*Zeroable)(nil)).Elem()
 
+// IsValueZero returns true if the reflect Value is a zero
 func IsValueZero(v reflect.Value) bool {
 	switch v.Kind() {
 	case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Slice:
@@ -88,6 +90,7 @@ func IsValueZero(v reflect.Value) bool {
 	return false
 }
 
+// IsStructZero returns true if the Value is a struct and all fields is zero
 func IsStructZero(v reflect.Value) bool {
 	if !v.IsValid() || v.NumField() == 0 {
 		return true
@@ -120,6 +123,7 @@ func IsStructZero(v reflect.Value) bool {
 	return true
 }
 
+// IsArrayZero returns true is a slice of array is zero
 func IsArrayZero(v reflect.Value) bool {
 	if !v.IsValid() || v.Len() == 0 {
 		return true
@@ -134,11 +138,13 @@ func IsArrayZero(v reflect.Value) bool {
 	return true
 }
 
+// represents all zero times
 const (
 	ZeroTime0 = "0000-00-00 00:00:00"
 	ZeroTime1 = "0001-01-01 00:00:00"
 )
 
+// IsTimeZero return true if a time is zero
 func IsTimeZero(t time.Time) bool {
 	return t.IsZero() || t.Format("2006-01-02 15:04:05") == ZeroTime0 ||
 		t.Format("2006-01-02 15:04:05") == ZeroTime1
diff --git a/log/logger_context.go b/log/logger_context.go
index 6b7252ef..46802576 100644
--- a/log/logger_context.go
+++ b/log/logger_context.go
@@ -42,6 +42,7 @@ var (
 // enumerate all the context keys
 var (
 	SessionIDKey      = "__xorm_session_id"
+	SessionKey        = "__xorm_session_key"
 	SessionShowSQLKey = "__xorm_show_sql"
 )
 
diff --git a/migrate/migrate.go b/migrate/migrate.go
index 82c58f90..19b4afe0 100644
--- a/migrate/migrate.go
+++ b/migrate/migrate.go
@@ -110,10 +110,7 @@ func (m *Migrate) RollbackLast() error {
 		return err
 	}
 
-	if err := m.RollbackMigration(lastRunnedMigration); err != nil {
-		return err
-	}
-	return nil
+	return m.RollbackMigration(lastRunnedMigration)
 }
 
 func (m *Migrate) getLastRunnedMigration() (*Migration, error) {
diff --git a/migrate/migrate_test.go b/migrate/migrate_test.go
index 19554f7e..3d7aa189 100644
--- a/migrate/migrate_test.go
+++ b/migrate/migrate_test.go
@@ -106,10 +106,7 @@ func TestInitSchema(t *testing.T) {
 		if err := tx.Sync2(&Person{}); err != nil {
 			return err
 		}
-		if err := tx.Sync2(&Pet{}); err != nil {
-			return err
-		}
-		return nil
+		return tx.Sync2(&Pet{})
 	})
 
 	err = m.Migrate()
diff --git a/names/mapper.go b/names/mapper.go
index 4aaf0844..b0ce8076 100644
--- a/names/mapper.go
+++ b/names/mapper.go
@@ -7,6 +7,7 @@ package names
 import (
 	"strings"
 	"sync"
+	"unsafe"
 )
 
 // Mapper represents a name convertation between struct's fields name and table's column name
@@ -15,6 +16,7 @@ type Mapper interface {
 	Table2Obj(string) string
 }
 
+// CacheMapper represents a cache mapper
 type CacheMapper struct {
 	oriMapper      Mapper
 	obj2tableCache map[string]string
@@ -23,12 +25,14 @@ type CacheMapper struct {
 	table2objMutex sync.RWMutex
 }
 
+// NewCacheMapper creates a cache mapper
 func NewCacheMapper(mapper Mapper) *CacheMapper {
 	return &CacheMapper{oriMapper: mapper, obj2tableCache: make(map[string]string),
 		table2objCache: make(map[string]string),
 	}
 }
 
+// Obj2Table implements Mapper
 func (m *CacheMapper) Obj2Table(o string) string {
 	m.obj2tableMutex.RLock()
 	t, ok := m.obj2tableCache[o]
@@ -44,6 +48,7 @@ func (m *CacheMapper) Obj2Table(o string) string {
 	return t
 }
 
+// Table2Obj implements Mapper
 func (m *CacheMapper) Table2Obj(t string) string {
 	m.table2objMutex.RLock()
 	o, ok := m.table2objCache[t]
@@ -59,15 +64,17 @@ func (m *CacheMapper) Table2Obj(t string) string {
 	return o
 }
 
-// SameMapper implements IMapper and provides same name between struct and
+// SameMapper implements Mapper and provides same name between struct and
 // database table
 type SameMapper struct {
 }
 
+// Obj2Table implements Mapper
 func (m SameMapper) Obj2Table(o string) string {
 	return o
 }
 
+// Table2Obj implements Mapper
 func (m SameMapper) Table2Obj(t string) string {
 	return t
 }
@@ -77,49 +84,57 @@ func (m SameMapper) Table2Obj(t string) string {
 type SnakeMapper struct {
 }
 
-func snakeCasedName(name string) string {
-	newstr := make([]rune, 0)
-	for idx, chr := range name {
-		if isUpper := 'A' <= chr && chr <= 'Z'; isUpper {
-			if idx > 0 {
-				newstr = append(newstr, '_')
-			}
-			chr -= ('A' - 'a')
-		}
-		newstr = append(newstr, chr)
-	}
-
-	return string(newstr)
+func b2s(b []byte) string {
+	return *(*string)(unsafe.Pointer(&b))
 }
 
+func snakeCasedName(name string) string {
+	newstr := make([]byte, 0, len(name)+1)
+	for i := 0; i < len(name); i++ {
+		c := name[i]
+		if isUpper := 'A' <= c && c <= 'Z'; isUpper {
+			if i > 0 {
+				newstr = append(newstr, '_')
+			}
+			c += 'a' - 'A'
+		}
+		newstr = append(newstr, c)
+	}
+
+	return b2s(newstr)
+}
+
+// Obj2Table implements Mapper
 func (mapper SnakeMapper) Obj2Table(name string) string {
 	return snakeCasedName(name)
 }
 
 func titleCasedName(name string) string {
-	newstr := make([]rune, 0)
+	newstr := make([]byte, 0, len(name))
 	upNextChar := true
 
 	name = strings.ToLower(name)
 
-	for _, chr := range name {
+	for i := 0; i < len(name); i++ {
+		c := name[i]
 		switch {
 		case upNextChar:
 			upNextChar = false
-			if 'a' <= chr && chr <= 'z' {
-				chr -= ('a' - 'A')
+			if 'a' <= c && c <= 'z' {
+				c -= 'a' - 'A'
 			}
-		case chr == '_':
+		case c == '_':
 			upNextChar = true
 			continue
 		}
 
-		newstr = append(newstr, chr)
+		newstr = append(newstr, c)
 	}
 
-	return string(newstr)
+	return b2s(newstr)
 }
 
+// Table2Obj implements Mapper
 func (mapper SnakeMapper) Table2Obj(name string) string {
 	return titleCasedName(name)
 }
@@ -161,10 +176,12 @@ func gonicCasedName(name string) string {
 	return strings.ToLower(string(newstr))
 }
 
+// Obj2Table implements Mapper
 func (mapper GonicMapper) Obj2Table(name string) string {
 	return gonicCasedName(name)
 }
 
+// Table2Obj implements Mapper
 func (mapper GonicMapper) Table2Obj(name string) string {
 	newstr := make([]rune, 0)
 
@@ -227,14 +244,17 @@ type PrefixMapper struct {
 	Prefix string
 }
 
+// Obj2Table implements Mapper
 func (mapper PrefixMapper) Obj2Table(name string) string {
 	return mapper.Prefix + mapper.Mapper.Obj2Table(name)
 }
 
+// Table2Obj implements Mapper
 func (mapper PrefixMapper) Table2Obj(name string) string {
 	return mapper.Mapper.Table2Obj(name[len(mapper.Prefix):])
 }
 
+// NewPrefixMapper creates a prefix mapper
 func NewPrefixMapper(mapper Mapper, prefix string) PrefixMapper {
 	return PrefixMapper{mapper, prefix}
 }
@@ -245,14 +265,17 @@ type SuffixMapper struct {
 	Suffix string
 }
 
+// Obj2Table implements Mapper
 func (mapper SuffixMapper) Obj2Table(name string) string {
 	return mapper.Mapper.Obj2Table(name) + mapper.Suffix
 }
 
+// Table2Obj implements Mapper
 func (mapper SuffixMapper) Table2Obj(name string) string {
 	return mapper.Mapper.Table2Obj(name[:len(name)-len(mapper.Suffix)])
 }
 
+// NewSuffixMapper creates a suffix mapper
 func NewSuffixMapper(mapper Mapper, suffix string) SuffixMapper {
 	return SuffixMapper{mapper, suffix}
 }
diff --git a/names/mapper_test.go b/names/mapper_test.go
index 0edfd2a8..a39cb569 100644
--- a/names/mapper_test.go
+++ b/names/mapper_test.go
@@ -5,6 +5,7 @@
 package names
 
 import (
+	"strings"
 	"testing"
 )
 
@@ -47,3 +48,23 @@ func TestGonicMapperToObj(t *testing.T) {
 		}
 	}
 }
+
+func BenchmarkSnakeCasedName(b *testing.B) {
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	s := strings.Repeat("FooBar", 32)
+	for i := 0; i < b.N; i++ {
+		_ = snakeCasedName(s)
+	}
+}
+
+func BenchmarkTitleCasedName(b *testing.B) {
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	s := strings.Repeat("foo_bar", 32)
+	for i := 0; i < b.N; i++ {
+		_ = titleCasedName(s)
+	}
+}
diff --git a/names/table_name.go b/names/table_name.go
index 0afb1ae3..cc0e9274 100644
--- a/names/table_name.go
+++ b/names/table_name.go
@@ -19,6 +19,7 @@ var (
 	tvCache     sync.Map
 )
 
+// GetTableName returns table name
 func GetTableName(mapper Mapper, v reflect.Value) string {
 	if v.Type().Implements(tpTableName) {
 		return v.Interface().(TableName).TableName()
diff --git a/schemas/column.go b/schemas/column.go
index 418629ac..5808b84d 100644
--- a/schemas/column.go
+++ b/schemas/column.go
@@ -5,12 +5,15 @@
 package schemas
 
 import (
+	"errors"
 	"fmt"
 	"reflect"
+	"strconv"
 	"strings"
 	"time"
 )
 
+// enumerates all database mapping way
 const (
 	TWOSIDES = iota + 1
 	ONLYTODB
@@ -49,6 +52,7 @@ type Column struct {
 func NewColumn(name, fieldName string, sqlType SQLType, len1, len2 int, nullable bool) *Column {
 	return &Column{
 		Name:            name,
+		IsJSON:          sqlType.IsJson(),
 		TableName:       "",
 		FieldName:       fieldName,
 		SQLType:         sqlType,
@@ -115,3 +119,17 @@ func (col *Column) ValueOfV(dataStruct *reflect.Value) (*reflect.Value, error) {
 
 	return &fieldValue, nil
 }
+
+// ConvertID converts id content to suitable type according column type
+func (col *Column) ConvertID(sid string) (interface{}, error) {
+	if col.SQLType.IsNumeric() {
+		n, err := strconv.ParseInt(sid, 10, 64)
+		if err != nil {
+			return nil, err
+		}
+		return n, nil
+	} else if col.SQLType.IsText() {
+		return sid, nil
+	}
+	return nil, errors.New("not supported")
+}
diff --git a/schemas/index.go b/schemas/index.go
index 9541250f..8f31af52 100644
--- a/schemas/index.go
+++ b/schemas/index.go
@@ -28,6 +28,7 @@ func NewIndex(name string, indexType int) *Index {
 	return &Index{true, name, indexType, make([]string, 0)}
 }
 
+// XName returns the special index name for the table
 func (index *Index) XName(tableName string) string {
 	if !strings.HasPrefix(index.Name, "UQE_") &&
 		!strings.HasPrefix(index.Name, "IDX_") {
@@ -43,11 +44,10 @@ func (index *Index) XName(tableName string) string {
 
 // AddColumn add columns which will be composite index
 func (index *Index) AddColumn(cols ...string) {
-	for _, col := range cols {
-		index.Cols = append(index.Cols, col)
-	}
+	index.Cols = append(index.Cols, cols...)
 }
 
+// Equal return true if the two Index is equal
 func (index *Index) Equal(dst *Index) bool {
 	if index.Type != dst.Type {
 		return false
diff --git a/schemas/pk.go b/schemas/pk.go
index 03916b44..da3c7899 100644
--- a/schemas/pk.go
+++ b/schemas/pk.go
@@ -11,13 +11,16 @@ import (
 	"xorm.io/xorm/internal/utils"
 )
 
+// PK represents primary key values
 type PK []interface{}
 
+// NewPK creates primay keys
 func NewPK(pks ...interface{}) *PK {
 	p := PK(pks)
 	return &p
 }
 
+// IsZero return true if primay keys are zero
 func (p *PK) IsZero() bool {
 	for _, k := range *p {
 		if utils.IsZero(k) {
@@ -27,6 +30,7 @@ func (p *PK) IsZero() bool {
 	return false
 }
 
+// ToString convert to SQL string
 func (p *PK) ToString() (string, error) {
 	buf := new(bytes.Buffer)
 	enc := gob.NewEncoder(buf)
@@ -34,6 +38,7 @@ func (p *PK) ToString() (string, error) {
 	return buf.String(), err
 }
 
+// FromString reads content to load primary keys
 func (p *PK) FromString(content string) error {
 	dec := gob.NewDecoder(bytes.NewBufferString(content))
 	err := dec.Decode(p)
diff --git a/schemas/quote.go b/schemas/quote.go
index c44abe25..71040ad9 100644
--- a/schemas/quote.go
+++ b/schemas/quote.go
@@ -16,10 +16,10 @@ type Quoter struct {
 }
 
 var (
-	// AlwaysFalseReverse always think it's not a reverse word
+	// AlwaysNoReserve always think it's not a reverse word
 	AlwaysNoReserve = func(string) bool { return false }
 
-	// AlwaysReverse always reverse the word
+	// AlwaysReserve always reverse the word
 	AlwaysReserve = func(string) bool { return true }
 
 	// CommanQuoteMark represnets the common quote mark
@@ -29,10 +29,12 @@ var (
 	CommonQuoter = Quoter{CommanQuoteMark, CommanQuoteMark, AlwaysReserve}
 )
 
+// IsEmpty return true if no prefix and suffix
 func (q Quoter) IsEmpty() bool {
 	return q.Prefix == 0 && q.Suffix == 0
 }
 
+// Quote quote a string
 func (q Quoter) Quote(s string) string {
 	var buf strings.Builder
 	q.QuoteTo(&buf, s)
@@ -59,12 +61,14 @@ func (q Quoter) Trim(s string) string {
 	return buf.String()
 }
 
+// Join joins a slice with quoters
 func (q Quoter) Join(a []string, sep string) string {
 	var b strings.Builder
 	q.JoinWrite(&b, a, sep)
 	return b.String()
 }
 
+// JoinWrite writes quoted content to a builder
 func (q Quoter) JoinWrite(b *strings.Builder, a []string, sep string) error {
 	if len(a) == 0 {
 		return nil
@@ -82,9 +86,7 @@ func (q Quoter) JoinWrite(b *strings.Builder, a []string, sep string) error {
 				return err
 			}
 		}
-		if s != "*" {
-			q.QuoteTo(b, strings.TrimSpace(s))
-		}
+		q.QuoteTo(b, strings.TrimSpace(s))
 	}
 	return nil
 }
@@ -143,7 +145,7 @@ func (q Quoter) quoteWordTo(buf *strings.Builder, word string) error {
 	}
 
 	isReserved := q.IsReserved(realWord)
-	if isReserved {
+	if isReserved && realWord != "*" {
 		if err := buf.WriteByte(q.Prefix); err != nil {
 			return err
 		}
@@ -151,7 +153,7 @@ func (q Quoter) quoteWordTo(buf *strings.Builder, word string) error {
 	if _, err := buf.WriteString(realWord); err != nil {
 		return err
 	}
-	if isReserved {
+	if isReserved && realWord != "*" {
 		return buf.WriteByte(q.Suffix)
 	}
 
diff --git a/schemas/quote_test.go b/schemas/quote_test.go
index 708b450e..8e351dc0 100644
--- a/schemas/quote_test.go
+++ b/schemas/quote_test.go
@@ -22,6 +22,7 @@ func TestAlwaysQuoteTo(t *testing.T) {
 			{"[mytable]", "`mytable`"},
 			{"[mytable]", `[mytable]`},
 			{`["mytable"]`, `"mytable"`},
+			{`[mytable].*`, `[mytable].*`},
 			{"[myschema].[mytable]", "myschema.mytable"},
 			{"[myschema].[mytable]", "`myschema`.mytable"},
 			{"[myschema].[mytable]", "myschema.`mytable`"},
@@ -65,6 +66,7 @@ func TestReversedQuoteTo(t *testing.T) {
 			{"[mytable]", "mytable"},
 			{"[mytable]", "`mytable`"},
 			{"[mytable]", `[mytable]`},
+			{"[mytable].*", `[mytable].*`},
 			{`"mytable"`, `"mytable"`},
 			{"myschema.[mytable]", "myschema.mytable"},
 			{"myschema.[mytable]", "`myschema`.mytable"},
@@ -98,6 +100,7 @@ func TestNoQuoteTo(t *testing.T) {
 			{"mytable", "mytable"},
 			{"mytable", "`mytable`"},
 			{"mytable", `[mytable]`},
+			{"mytable.*", `[mytable].*`},
 			{`"mytable"`, `"mytable"`},
 			{"myschema.mytable", "myschema.mytable"},
 			{"myschema.mytable", "`myschema`.mytable"},
@@ -127,6 +130,8 @@ func TestJoin(t *testing.T) {
 
 	assert.EqualValues(t, "[a],[b]", quoter.Join([]string{"a", " b"}, ","))
 
+	assert.EqualValues(t, "[a].*,[b].[c]", quoter.Join([]string{"a.*", " b.c"}, ","))
+
 	assert.EqualValues(t, "[f1], [f2], [f3]", quoter.Join(cols, ", "))
 
 	quoter.IsReserved = AlwaysNoReserve
@@ -134,11 +139,11 @@ func TestJoin(t *testing.T) {
 }
 
 func TestStrings(t *testing.T) {
-	cols := []string{"f1", "f2", "t3.f3"}
+	cols := []string{"f1", "f2", "t3.f3", "t4.*"}
 	quoter := Quoter{'[', ']', AlwaysReserve}
 
 	quotedCols := quoter.Strings(cols)
-	assert.EqualValues(t, []string{"[f1]", "[f2]", "[t3].[f3]"}, quotedCols)
+	assert.EqualValues(t, []string{"[f1]", "[f2]", "[t3].[f3]", "[t4].*"}, quotedCols)
 }
 
 func TestTrim(t *testing.T) {
diff --git a/schemas/table.go b/schemas/table.go
index 38596991..bfa517aa 100644
--- a/schemas/table.go
+++ b/schemas/table.go
@@ -5,7 +5,9 @@
 package schemas
 
 import (
+	"fmt"
 	"reflect"
+	"strconv"
 	"strings"
 )
 
@@ -28,6 +30,7 @@ type Table struct {
 	Comment       string
 }
 
+// NewEmptyTable creates an empty table
 func NewEmptyTable() *Table {
 	return NewTable("", nil)
 }
@@ -44,23 +47,21 @@ func NewTable(name string, t reflect.Type) *Table {
 	}
 }
 
+// Columns returns table's columns
 func (table *Table) Columns() []*Column {
 	return table.columns
 }
 
+// ColumnsSeq returns table's column names according sequence
 func (table *Table) ColumnsSeq() []string {
 	return table.columnsSeq
 }
 
 func (table *Table) columnsByName(name string) []*Column {
-	for k, cols := range table.columnsMap {
-		if strings.EqualFold(k, name) {
-			return cols
-		}
-	}
-	return nil
+	return table.columnsMap[strings.ToLower(name)]
 }
 
+// GetColumn returns column according column name, if column not found, return nil
 func (table *Table) GetColumn(name string) *Column {
 	cols := table.columnsByName(name)
 	if cols != nil {
@@ -70,6 +71,7 @@ func (table *Table) GetColumn(name string) *Column {
 	return nil
 }
 
+// GetColumnIdx returns column according name and idx
 func (table *Table) GetColumnIdx(name string, idx int) *Column {
 	cols := table.columnsByName(name)
 	if cols != nil && idx < len(cols) {
@@ -88,23 +90,28 @@ func (table *Table) PKColumns() []*Column {
 	return columns
 }
 
+// ColumnType returns a column's type
 func (table *Table) ColumnType(name string) reflect.Type {
 	t, _ := table.Type.FieldByName(name)
 	return t.Type
 }
 
+// AutoIncrColumn returns autoincrement column
 func (table *Table) AutoIncrColumn() *Column {
 	return table.GetColumn(table.AutoIncrement)
 }
 
+// VersionColumn returns version column's information
 func (table *Table) VersionColumn() *Column {
 	return table.GetColumn(table.Version)
 }
 
+// UpdatedColumn returns updated column's information
 func (table *Table) UpdatedColumn() *Column {
 	return table.GetColumn(table.Updated)
 }
 
+// DeletedColumn returns deleted column's information
 func (table *Table) DeletedColumn() *Column {
 	return table.GetColumn(table.Deleted)
 }
@@ -144,3 +151,45 @@ func (table *Table) AddColumn(col *Column) {
 func (table *Table) AddIndex(index *Index) {
 	table.Indexes[index.Name] = index
 }
+
+// IDOfV get id from one value of struct
+func (table *Table) IDOfV(rv reflect.Value) (PK, error) {
+	v := reflect.Indirect(rv)
+	pk := make([]interface{}, len(table.PrimaryKeys))
+	for i, col := range table.PKColumns() {
+		var err error
+
+		fieldName := col.FieldName
+		for {
+			parts := strings.SplitN(fieldName, ".", 2)
+			if len(parts) == 1 {
+				break
+			}
+
+			v = v.FieldByName(parts[0])
+			if v.Kind() == reflect.Ptr {
+				v = v.Elem()
+			}
+			if v.Kind() != reflect.Struct {
+				return nil, fmt.Errorf("Unsupported read value of column %s from field %s", col.Name, col.FieldName)
+			}
+			fieldName = parts[1]
+		}
+
+		pkField := v.FieldByName(fieldName)
+		switch pkField.Kind() {
+		case reflect.String:
+			pk[i], err = col.ConvertID(pkField.String())
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+			pk[i], err = col.ConvertID(strconv.FormatInt(pkField.Int(), 10))
+		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+			// id of uint will be converted to int64
+			pk[i], err = col.ConvertID(strconv.FormatUint(pkField.Uint(), 10))
+		}
+
+		if err != nil {
+			return nil, err
+		}
+	}
+	return PK(pk), nil
+}
diff --git a/schemas/type.go b/schemas/type.go
index 89459a4d..fc02f015 100644
--- a/schemas/type.go
+++ b/schemas/type.go
@@ -11,8 +11,10 @@ import (
 	"time"
 )
 
+// DBType represents a database type
 type DBType string
 
+// enumerates all database types
 const (
 	POSTGRES DBType = "postgres"
 	SQLITE   DBType = "sqlite3"
@@ -28,6 +30,7 @@ type SQLType struct {
 	DefaultLength2 int
 }
 
+// enumerates all columns types
 const (
 	UNKNOW_TYPE = iota
 	TEXT_TYPE
@@ -37,6 +40,7 @@ const (
 	ARRAY_TYPE
 )
 
+// IsType reutrns ture if the column type is the same as the parameter
 func (s *SQLType) IsType(st int) bool {
 	if t, ok := SqlTypes[s.Name]; ok && t == st {
 		return true
@@ -44,38 +48,53 @@ func (s *SQLType) IsType(st int) bool {
 	return false
 }
 
+// IsText returns true if column is a text type
 func (s *SQLType) IsText() bool {
 	return s.IsType(TEXT_TYPE)
 }
 
+// IsBlob returns true if column is a binary type
 func (s *SQLType) IsBlob() bool {
 	return s.IsType(BLOB_TYPE)
 }
 
+// IsTime returns true if column is a time type
 func (s *SQLType) IsTime() bool {
 	return s.IsType(TIME_TYPE)
 }
 
+// IsNumeric returns true if column is a numeric type
 func (s *SQLType) IsNumeric() bool {
 	return s.IsType(NUMERIC_TYPE)
 }
 
+// IsArray returns true if column is an array type
 func (s *SQLType) IsArray() bool {
 	return s.IsType(ARRAY_TYPE)
 }
 
+// IsJson returns true if column is an array type
 func (s *SQLType) IsJson() bool {
 	return s.Name == Json || s.Name == Jsonb
 }
 
+// IsXML returns true if column is an xml type
+func (s *SQLType) IsXML() bool {
+	return s.Name == XML
+}
+
+// enumerates all the database column types
 var (
-	Bit       = "BIT"
-	TinyInt   = "TINYINT"
-	SmallInt  = "SMALLINT"
-	MediumInt = "MEDIUMINT"
-	Int       = "INT"
-	Integer   = "INTEGER"
-	BigInt    = "BIGINT"
+	Bit            = "BIT"
+	UnsignedBit    = "UNSIGNED BIT"
+	TinyInt        = "TINYINT"
+	SmallInt       = "SMALLINT"
+	MediumInt      = "MEDIUMINT"
+	Int            = "INT"
+	UnsignedInt    = "UNSIGNED INT"
+	Integer        = "INTEGER"
+	BigInt         = "BIGINT"
+	UnsignedBigInt = "UNSIGNED BIGINT"
 
 	Enum = "ENUM"
 	Set  = "SET"
@@ -128,22 +147,28 @@ var (
 	Json  = "JSON"
 	Jsonb = "JSONB"
 
+	XML   = "XML"
 	Array = "ARRAY"
 
 	SqlTypes = map[string]int{
-		Bit:       NUMERIC_TYPE,
-		TinyInt:   NUMERIC_TYPE,
-		SmallInt:  NUMERIC_TYPE,
-		MediumInt: NUMERIC_TYPE,
-		Int:       NUMERIC_TYPE,
-		Integer:   NUMERIC_TYPE,
-		BigInt:    NUMERIC_TYPE,
+		Bit:            NUMERIC_TYPE,
+		UnsignedBit:    NUMERIC_TYPE,
+		TinyInt:        NUMERIC_TYPE,
+		SmallInt:       NUMERIC_TYPE,
+		MediumInt:      NUMERIC_TYPE,
+		Int:            NUMERIC_TYPE,
+		UnsignedInt:    NUMERIC_TYPE,
+		Integer:        NUMERIC_TYPE,
+		BigInt:         NUMERIC_TYPE,
+		UnsignedBigInt: NUMERIC_TYPE,
 
 		Enum:  TEXT_TYPE,
 		Set:   TEXT_TYPE,
 		Json:  TEXT_TYPE,
 		Jsonb: TEXT_TYPE,
 
+		XML: TEXT_TYPE,
+
 		Char:       TEXT_TYPE,
 		NChar:      TEXT_TYPE,
 		Varchar:    TEXT_TYPE,
@@ -197,53 +222,55 @@ var (
 
 // !nashtsai! treat following var as interal const values, these are used for reflect.TypeOf comparison
 var (
-	c_EMPTY_STRING       string
-	c_BOOL_DEFAULT       bool
-	c_BYTE_DEFAULT       byte
-	c_COMPLEX64_DEFAULT  complex64
-	c_COMPLEX128_DEFAULT complex128
-	c_FLOAT32_DEFAULT    float32
-	c_FLOAT64_DEFAULT    float64
-	c_INT64_DEFAULT      int64
-	c_UINT64_DEFAULT     uint64
-	c_INT32_DEFAULT      int32
-	c_UINT32_DEFAULT     uint32
-	c_INT16_DEFAULT      int16
-	c_UINT16_DEFAULT     uint16
-	c_INT8_DEFAULT       int8
-	c_UINT8_DEFAULT      uint8
-	c_INT_DEFAULT        int
-	c_UINT_DEFAULT       uint
-	c_TIME_DEFAULT       time.Time
+	emptyString       string
+	boolDefault       bool
+	byteDefault       byte
+	complex64Default  complex64
+	complex128Default complex128
+	float32Default    float32
+	float64Default    float64
+	int64Default      int64
+	uint64Default     uint64
+	int32Default      int32
+	uint32Default     uint32
+	int16Default      int16
+	uint16Default     uint16
+	int8Default       int8
+	uint8Default      uint8
+	intDefault        int
+	uintDefault       uint
+	timeDefault       time.Time
 )
 
+// enumerates all types
 var (
-	IntType   = reflect.TypeOf(c_INT_DEFAULT)
-	Int8Type  = reflect.TypeOf(c_INT8_DEFAULT)
-	Int16Type = reflect.TypeOf(c_INT16_DEFAULT)
-	Int32Type = reflect.TypeOf(c_INT32_DEFAULT)
-	Int64Type = reflect.TypeOf(c_INT64_DEFAULT)
+	IntType   = reflect.TypeOf(intDefault)
+	Int8Type  = reflect.TypeOf(int8Default)
+	Int16Type = reflect.TypeOf(int16Default)
+	Int32Type = reflect.TypeOf(int32Default)
+	Int64Type = reflect.TypeOf(int64Default)
 
-	UintType   = reflect.TypeOf(c_UINT_DEFAULT)
-	Uint8Type  = reflect.TypeOf(c_UINT8_DEFAULT)
-	Uint16Type = reflect.TypeOf(c_UINT16_DEFAULT)
-	Uint32Type = reflect.TypeOf(c_UINT32_DEFAULT)
-	Uint64Type = reflect.TypeOf(c_UINT64_DEFAULT)
+	UintType   = reflect.TypeOf(uintDefault)
+	Uint8Type  = reflect.TypeOf(uint8Default)
+	Uint16Type = reflect.TypeOf(uint16Default)
+	Uint32Type = reflect.TypeOf(uint32Default)
+	Uint64Type = reflect.TypeOf(uint64Default)
 
-	Float32Type = reflect.TypeOf(c_FLOAT32_DEFAULT)
-	Float64Type = reflect.TypeOf(c_FLOAT64_DEFAULT)
+	Float32Type = reflect.TypeOf(float32Default)
+	Float64Type = reflect.TypeOf(float64Default)
 
-	Complex64Type  = reflect.TypeOf(c_COMPLEX64_DEFAULT)
-	Complex128Type = reflect.TypeOf(c_COMPLEX128_DEFAULT)
+	Complex64Type  = reflect.TypeOf(complex64Default)
+	Complex128Type = reflect.TypeOf(complex128Default)
 
-	StringType = reflect.TypeOf(c_EMPTY_STRING)
-	BoolType   = reflect.TypeOf(c_BOOL_DEFAULT)
-	ByteType   = reflect.TypeOf(c_BYTE_DEFAULT)
+	StringType = reflect.TypeOf(emptyString)
+	BoolType   = reflect.TypeOf(boolDefault)
+	ByteType   = reflect.TypeOf(byteDefault)
 	BytesType  = reflect.SliceOf(ByteType)
 
-	TimeType = reflect.TypeOf(c_TIME_DEFAULT)
+	TimeType = reflect.TypeOf(timeDefault)
 )
 
+// enumerates all types
 var (
 	PtrIntType   = reflect.PtrTo(IntType)
 	PtrInt8Type  = reflect.PtrTo(Int8Type)
@@ -273,10 +300,14 @@ var (
 // Type2SQLType generate SQLType acorrding Go's type
 func Type2SQLType(t reflect.Type) (st SQLType) {
 	switch k := t.Kind(); k {
-	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32:
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32:
 		st = SQLType{Int, 0, 0}
-	case reflect.Int64, reflect.Uint64:
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32:
+		st = SQLType{UnsignedInt, 0, 0}
+	case reflect.Int64:
 		st = SQLType{BigInt, 0, 0}
+	case reflect.Uint64:
+		st = SQLType{UnsignedBigInt, 0, 0}
 	case reflect.Float32:
 		st = SQLType{Float, 0, 0}
 	case reflect.Float64:
@@ -284,7 +315,7 @@ func Type2SQLType(t reflect.Type) (st SQLType) {
 	case reflect.Complex64, reflect.Complex128:
 		st = SQLType{Varchar, 64, 0}
 	case reflect.Array, reflect.Slice, reflect.Map:
-		if t.Elem() == reflect.TypeOf(c_BYTE_DEFAULT) {
+		if t.Elem() == reflect.TypeOf(byteDefault) {
 			st = SQLType{Blob, 0, 0}
 		} else {
 			st = SQLType{Text, 0, 0}
@@ -308,7 +339,7 @@ func Type2SQLType(t reflect.Type) (st SQLType) {
 	return
 }
 
-// default sql type change to go types
+// SQLType2Type convert default sql type change to go types
 func SQLType2Type(st SQLType) reflect.Type {
 	name := strings.ToUpper(st.Name)
 	switch name {
@@ -327,7 +358,7 @@ func SQLType2Type(st SQLType) reflect.Type {
 	case Bool:
 		return reflect.TypeOf(true)
 	case DateTime, Date, Time, TimeStamp, TimeStampz, SmallDateTime, Year:
-		return reflect.TypeOf(c_TIME_DEFAULT)
+		return reflect.TypeOf(timeDefault)
 	case Decimal, Numeric, Money, SmallMoney:
 		return reflect.TypeOf("")
 	default:
diff --git a/session.go b/session.go
index 761b1415..d5ccb6dc 100644
--- a/session.go
+++ b/session.go
@@ -107,7 +107,7 @@ func newSession(engine *Engine) *Session {
 		ctx = engine.defaultContext
 	}
 
-	return &Session{
+	session := &Session{
 		ctx:    ctx,
 		engine: engine,
 		tx:     nil,
@@ -136,6 +136,10 @@ func newSession(engine *Engine) *Session {
 
 		sessionType: engineSession,
 	}
+	if engine.logSessionID {
+		session.ctx = context.WithValue(session.ctx, log.SessionKey, session)
+	}
+	return session
 }
 
 // Close release the connection from pool
@@ -165,6 +169,11 @@ func (session *Session) db() *core.DB {
 	return session.engine.db
 }
 
+// Engine returns session Engine
+func (session *Session) Engine() *Engine {
+	return session.engine
+}
+
 func (session *Session) getQueryer() core.Queryer {
 	if session.tx != nil {
 		return session.tx
@@ -495,7 +504,7 @@ func (session *Session) slice2Bean(scanResults []interface{}, fields []string, b
 		fieldType := fieldValue.Type()
 		hasAssigned := false
 
-		if col.SQLType.IsJson() {
+		if col.IsJSON {
 			var bs []byte
 			if rawValueType.Kind() == reflect.String {
 				bs = []byte(vv.String())
@@ -675,7 +684,7 @@ func (session *Session) slice2Bean(scanResults []interface{}, fields []string, b
 					session.engine.logger.Errorf("sql.Sanner error: %v", err)
 					hasAssigned = false
 				}
-			} else if col.SQLType.IsJson() {
+			} else if col.IsJSON {
 				if rawValueType.Kind() == reflect.String {
 					hasAssigned = true
 					x := reflect.New(fieldType)
@@ -887,7 +896,7 @@ func (session *Session) incrVersionFieldValue(fieldValue *reflect.Value) {
 	}
 }
 
-// ContextHook sets the context on this session
+// Context sets the context on this session
 func (session *Session) Context(ctx context.Context) *Session {
 	session.ctx = ctx
 	return session
diff --git a/session_find.go b/session_find.go
index 3bc6a642..0daea005 100644
--- a/session_find.go
+++ b/session_find.go
@@ -57,9 +57,18 @@ func (session *Session) FindAndCount(rowsSlicePtr interface{}, condiBean ...inte
 	if session.statement.SelectStr != "" {
 		session.statement.SelectStr = ""
 	}
+	if len(session.statement.ColumnMap) > 0 {
+		session.statement.ColumnMap = []string{}
+	}
 	if session.statement.OrderStr != "" {
 		session.statement.OrderStr = ""
 	}
+	if session.statement.LimitN != nil {
+		session.statement.LimitN = nil
+	}
+	if session.statement.Start > 0 {
+		session.statement.Start = 0
+	}
 
 	// session has stored the conditions so we use `unscoped` to avoid duplicated condition.
 	return session.Unscoped().Count(reflect.New(sliceElementType).Interface())
@@ -320,7 +329,7 @@ func (session *Session) cacheFind(t reflect.Type, sqlStr string, rowsSlicePtr in
 			}
 			var pk schemas.PK = make([]interface{}, len(table.PrimaryKeys))
 			for i, col := range table.PKColumns() {
-				pk[i], err = session.engine.idTypeAssertion(col, res[i])
+				pk[i], err = col.ConvertID(res[i])
 				if err != nil {
 					return err
 				}
@@ -370,7 +379,7 @@ func (session *Session) cacheFind(t reflect.Type, sqlStr string, rowsSlicePtr in
 		} else {
 			session.engine.logger.Debugf("[cache] cache hit bean: %v, %v, %v", tableName, id, bean)
 
-			pk, err := session.engine.IDOf(bean)
+			pk, err := table.IDOfV(reflect.ValueOf(bean))
 			if err != nil {
 				return err
 			}
@@ -419,7 +428,6 @@ func (session *Session) cacheFind(t reflect.Type, sqlStr string, rowsSlicePtr in
 		if err != nil {
 			return err
 		}
-
 		session.statement = statement
 
 		vs := reflect.Indirect(reflect.ValueOf(beans))
@@ -428,7 +436,7 @@ func (session *Session) cacheFind(t reflect.Type, sqlStr string, rowsSlicePtr in
 			if rv.Kind() != reflect.Ptr {
 				rv = rv.Addr()
 			}
-			id, err := session.engine.idOfV(rv)
+			id, err := table.IDOfV(rv)
 			if err != nil {
 				return err
 			}
diff --git a/session_get.go b/session_get.go
index afedcd1f..e303176d 100644
--- a/session_get.go
+++ b/session_get.go
@@ -16,6 +16,11 @@ import (
 	"xorm.io/xorm/schemas"
 )
 
+var (
+	// ErrObjectIsNil return error of object is nil
+	ErrObjectIsNil = errors.New("object should not be nil")
+)
+
 // Get retrieve one record from database, bean's non-empty fields
 // will be as conditions
 func (session *Session) Get(bean interface{}) (bool, error) {
@@ -37,6 +42,8 @@ func (session *Session) get(bean interface{}) (bool, error) {
 		return false, errors.New("needs a pointer to a value")
 	} else if beanValue.Elem().Kind() == reflect.Ptr {
 		return false, errors.New("a pointer to a pointer is not allowed")
+	} else if beanValue.IsNil() {
+		return false, ErrObjectIsNil
 	}
 
 	if beanValue.Elem().Kind() == reflect.Struct {
diff --git a/session_schema.go b/session_schema.go
index 9ccf8abe..7d36ae7f 100644
--- a/session_schema.go
+++ b/session_schema.go
@@ -448,27 +448,43 @@ func (session *Session) ImportFile(ddlPath string) ([]sql.Result, error) {
 
 // Import SQL DDL from io.Reader
 func (session *Session) Import(r io.Reader) ([]sql.Result, error) {
-	var results []sql.Result
-	var lastError error
-	scanner := bufio.NewScanner(r)
+	var (
+		results       []sql.Result
+		lastError     error
+		inSingleQuote bool
+		startComment  bool
+	)
 
-	var inSingleQuote bool
+	scanner := bufio.NewScanner(r)
 	semiColSpliter := func(data []byte, atEOF bool) (advance int, token []byte, err error) {
 		if atEOF && len(data) == 0 {
 			return 0, nil, nil
 		}
+		var oriInSingleQuote = inSingleQuote
 		for i, b := range data {
-			if b == '\'' {
-				inSingleQuote = !inSingleQuote
-			}
-			if !inSingleQuote && b == ';' {
-				return i + 1, data[0:i], nil
+			if startComment {
+				if b == '\n' {
+					startComment = false
+				}
+			} else {
+				if i > 0 && data[i-1] == '-' && data[i] == '-' {
+					startComment = true
+					continue
+				}
+
+				if b == '\'' {
+					inSingleQuote = !inSingleQuote
+				}
+				if !inSingleQuote && b == ';' {
+					return i + 1, data[0:i], nil
+				}
 			}
 		}
 		// If we're at EOF, we have a final, non-terminated line. Return it.
 		if atEOF {
 			return len(data), data, nil
 		}
+		inSingleQuote = oriInSingleQuote
 		// Request more data.
 		return 0, nil, nil
 	}
@@ -479,10 +495,10 @@ func (session *Session) Import(r io.Reader) ([]sql.Result, error) {
 		query := strings.Trim(scanner.Text(), " \t\n\r")
 		if len(query) > 0 {
 			result, err := session.Exec(query)
-			results = append(results, result)
 			if err != nil {
 				return nil, err
 			}
+			results = append(results, result)
 		}
 	}
 
diff --git a/session_tx.go b/session_tx.go
index cd23cf89..8763784c 100644
--- a/session_tx.go
+++ b/session_tx.go
@@ -4,12 +4,6 @@
 
 package xorm
 
-import (
-	"time"
-
-	"xorm.io/xorm/log"
-)
-
 // Begin a transaction
 func (session *Session) Begin() error {
 	if session.isAutoCommit {
@@ -33,24 +27,7 @@ func (session *Session) Rollback() error {
 		session.isCommitedOrRollbacked = true
 		session.isAutoCommit = true
 
-		start := time.Now()
-		needSQL := session.DB().NeedLogSQL(session.ctx)
-		if needSQL {
-			session.engine.logger.BeforeSQL(log.LogContext{
-				Ctx: session.ctx,
-				SQL: "ROLL BACK",
-			})
-		}
-		err := session.tx.Rollback()
-		if needSQL {
-			session.engine.logger.AfterSQL(log.LogContext{
-				Ctx:         session.ctx,
-				SQL:         "ROLL BACK",
-				ExecuteTime: time.Now().Sub(start),
-				Err:         err,
-			})
-		}
-		return err
+		return session.tx.Rollback()
 	}
 	return nil
 }
@@ -62,25 +39,7 @@ func (session *Session) Commit() error {
 		session.isCommitedOrRollbacked = true
 		session.isAutoCommit = true
 
-		start := time.Now()
-		needSQL := session.DB().NeedLogSQL(session.ctx)
-		if needSQL {
-			session.engine.logger.BeforeSQL(log.LogContext{
-				Ctx: session.ctx,
-				SQL: "COMMIT",
-			})
-		}
-		err := session.tx.Commit()
-		if needSQL {
-			session.engine.logger.AfterSQL(log.LogContext{
-				Ctx:         session.ctx,
-				SQL:         "COMMIT",
-				ExecuteTime: time.Now().Sub(start),
-				Err:         err,
-			})
-		}
-
-		if err != nil {
+		if err := session.tx.Commit(); err != nil {
 			return err
 		}
 
@@ -125,3 +84,8 @@ func (session *Session) Commit() error {
 	}
 	return nil
 }
+
+// IsInTx if current session is in a transaction
+func (session *Session) IsInTx() bool {
+	return !session.isAutoCommit
+}
diff --git a/session_update.go b/session_update.go
index 62116c47..0adac25e 100644
--- a/session_update.go
+++ b/session_update.go
@@ -206,7 +206,11 @@ func (session *Session) Update(bean interface{}, condiBean ...interface{}) (int6
 			colNames = append(colNames, session.engine.Quote(table.Updated)+" = ?")
 			col := table.UpdatedColumn()
 			val, t := session.engine.nowTime(col)
-			args = append(args, val)
+			if session.engine.dialect.URI().DBType == schemas.ORACLE {
+				args = append(args, t)
+			} else {
+				args = append(args, val)
+			}
 
 			var colName = col.Name
 			if isStruct {
@@ -269,8 +273,15 @@ func (session *Session) Update(bean interface{}, condiBean ...interface{}) (int6
 					k = ct.Elem().Kind()
 				}
 				if k == reflect.Struct {
+					var refTable = session.statement.RefTable
+					if refTable == nil {
+						refTable, err = session.engine.TableInfo(condiBean[0])
+						if err != nil {
+							return 0, err
+						}
+					}
 					var err error
-					autoCond, err = session.statement.BuildConds(session.statement.RefTable, condiBean[0], true, true, false, true, false)
+					autoCond, err = session.statement.BuildConds(refTable, condiBean[0], true, true, false, true, false)
 					if err != nil {
 						return 0, err
 					}
diff --git a/tags/parser.go b/tags/parser.go
index add30a13..5ad67b53 100644
--- a/tags/parser.go
+++ b/tags/parser.go
@@ -21,9 +21,11 @@ import (
 )
 
 var (
+	// ErrUnsupportedType represents an unsupported type error
 	ErrUnsupportedType = errors.New("Unsupported type")
 )
 
+// Parser represents a parser for xorm tag
 type Parser struct {
 	identifier   string
 	dialect      dialects.Dialect
@@ -34,6 +36,7 @@ type Parser struct {
 	tableCache   sync.Map // map[reflect.Type]*schemas.Table
 }
 
+// NewParser creates a tag parser
 func NewParser(identifier string, dialect dialects.Dialect, tableMapper, columnMapper names.Mapper, cacherMgr *caches.Manager) *Parser {
 	return &Parser{
 		identifier:   identifier,
@@ -45,24 +48,35 @@ func NewParser(identifier string, dialect dialects.Dialect, tableMapper, columnM
 	}
 }
 
+// GetTableMapper returns table mapper
 func (parser *Parser) GetTableMapper() names.Mapper {
 	return parser.tableMapper
 }
 
+// SetTableMapper sets table mapper
 func (parser *Parser) SetTableMapper(mapper names.Mapper) {
 	parser.ClearCaches()
 	parser.tableMapper = mapper
 }
 
+// GetColumnMapper returns column mapper
 func (parser *Parser) GetColumnMapper() names.Mapper {
 	return parser.columnMapper
 }
 
+// SetColumnMapper sets column mapper
 func (parser *Parser) SetColumnMapper(mapper names.Mapper) {
 	parser.ClearCaches()
 	parser.columnMapper = mapper
 }
 
+// SetIdentifier sets tag identifier
+func (parser *Parser) SetIdentifier(identifier string) {
+	parser.ClearCaches()
+	parser.identifier = identifier
+}
+
+// ParseWithCache parse a struct with cache
 func (parser *Parser) ParseWithCache(v reflect.Value) (*schemas.Table, error) {
 	t := v.Type()
 	tableI, ok := parser.tableCache.Load(t)
@@ -253,7 +267,7 @@ func (parser *Parser) Parse(v reflect.Value) (*schemas.Table, error) {
 					addIndex(indexName, table, col, indexType)
 				}
 			}
-		} else {
+		} else if fieldValue.CanSet() {
 			var sqlType schemas.SQLType
 			if fieldValue.CanAddr() {
 				if _, ok := fieldValue.Addr().Interface().(convert.Conversion); ok {
@@ -272,6 +286,8 @@ func (parser *Parser) Parse(v reflect.Value) (*schemas.Table, error) {
 			if fieldType.Kind() == reflect.Int64 && (strings.ToUpper(col.FieldName) == "ID" || strings.HasSuffix(strings.ToUpper(col.FieldName), ".ID")) {
 				idFieldColName = col.Name
 			}
+		} else {
+			continue
 		}
 		if col.IsAutoIncrement {
 			col.Nullable = false
diff --git a/tags/parser_test.go b/tags/parser_test.go
index 6065bf2e..c3bf8051 100644
--- a/tags/parser_test.go
+++ b/tags/parser_test.go
@@ -42,3 +42,64 @@ func TestParseTableName(t *testing.T) {
 	assert.NoError(t, err)
 	assert.EqualValues(t, "p_parseTableName", table.Name)
 }
+
+func TestUnexportField(t *testing.T) {
+	parser := NewParser(
+		"xorm",
+		dialects.QueryDialect("mysql"),
+		names.SnakeMapper{},
+		names.SnakeMapper{},
+		caches.NewManager(),
+	)
+
+	type VanilaStruct struct {
+		private int
+		Public  int
+	}
+	table, err := parser.Parse(reflect.ValueOf(new(VanilaStruct)))
+	assert.NoError(t, err)
+	assert.EqualValues(t, "vanila_struct", table.Name)
+	assert.EqualValues(t, 1, len(table.Columns()))
+
+	for _, col := range table.Columns() {
+		assert.EqualValues(t, "public", col.Name)
+		assert.NotEqual(t, "private", col.Name)
+	}
+
+	type TaggedStruct struct {
+		private int `xorm:"private"`
+		Public  int `xorm:"-"`
+	}
+	table, err = parser.Parse(reflect.ValueOf(new(TaggedStruct)))
+	assert.NoError(t, err)
+	assert.EqualValues(t, "tagged_struct", table.Name)
+	assert.EqualValues(t, 1, len(table.Columns()))
+
+	for _, col := range table.Columns() {
+		assert.EqualValues(t, "private", col.Name)
+		assert.NotEqual(t, "public", col.Name)
+	}
+}
+
+func TestParseWithOtherIdentifier(t *testing.T) {
+	parser := NewParser(
+		"xorm",
+		dialects.QueryDialect("mysql"),
+		names.GonicMapper{},
+		names.SnakeMapper{},
+		caches.NewManager(),
+	)
+
+	type StructWithDBTag struct {
+		FieldFoo string `db:"foo"`
+	}
+	parser.SetIdentifier("db")
+	table, err := parser.Parse(reflect.ValueOf(new(StructWithDBTag)))
+	assert.NoError(t, err)
+	assert.EqualValues(t, "struct_with_db_tag", table.Name)
+	assert.EqualValues(t, 1, len(table.Columns()))
+
+	for _, col := range table.Columns() {
+		assert.EqualValues(t, "foo", col.Name)
+	}
+}
diff --git a/tags/tag.go b/tags/tag.go
index ee3f1e82..bb5b5838 100644
--- a/tags/tag.go
+++ b/tags/tag.go
@@ -226,6 +226,9 @@ func CommentTagHandler(ctx *Context) error {
 // SQLTypeTagHandler describes SQL Type tag handler
 func SQLTypeTagHandler(ctx *Context) error {
 	ctx.col.SQLType = schemas.SQLType{Name: ctx.tagName}
+	if strings.EqualFold(ctx.tagName, "JSON") {
+		ctx.col.IsJSON = true
+	}
 	if len(ctx.params) > 0 {
 		if ctx.tagName == schemas.Enum {
 			ctx.col.EnumOptions = make(map[string]int)