diff --git a/QuickStart.md b/QuickStart.md
index 00d24625..b2c6cfc5 100644
--- a/QuickStart.md
+++ b/QuickStart.md
@@ -232,6 +232,9 @@ fmt.Println(user.Id)
 * OrderBy()
 按照指定的顺序进行排序
 
+* NoAutoTime()
+如果此方法执行，则此次生成的语句中Created和Updated字段将不自动赋值为当前时间
+
 * In(string, …interface{})
 某字段在一些值中
 
@@ -310,9 +313,11 @@ affected, err := engine.Id(id).Update(&user)
 删除数据`Delete`方法，参数为struct的指针并且成为查询条件。
 ```Go
 user := new(User)
-engine.Id(id).Delete(user)
+affected, err := engine.Id(id).Delete(user)
 ```
 
+`Delete`的返回值第一个参数为删除的记录数，第二个参数为错误。
+
 <a name="90" id="90"></a>
 ## 9.执行SQL查询
 
diff --git a/base_test.go b/base_test.go
index 4147ddd9..800d4be7 100644
--- a/base_test.go
+++ b/base_test.go
@@ -778,6 +778,16 @@ func testCreatedAndUpdated(engine *Engine, t *testing.T) {
 		t.Error(err)
 		panic(err)
 	}
+
+	u.Id = 0
+	u.Created = time.Now().Add(-time.Hour * 24 * 365)
+	u.Updated = u.Created
+	fmt.Println(u)
+	_, err = engine.NoAutoTime().Insert(u)
+	if err != nil {
+		t.Error(err)
+		panic(err)
+	}
 }
 
 type IndexOrUnique struct {
diff --git a/cache.go b/cache.go
new file mode 100644
index 00000000..8ae8e970
--- /dev/null
+++ b/cache.go
@@ -0,0 +1,173 @@
+package xorm
+
+import (
+	"container/list"
+	//"encoding/json"
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+	"sync"
+)
+
+type CacheStore interface {
+	Put(key, value interface{}) error
+	Get(key interface{}) (interface{}, error)
+	Del(key interface{}) error
+}
+
+type MemoryStore struct {
+	store map[interface{}]interface{}
+	mutex sync.Mutex
+}
+
+func NewMemoryStore() *MemoryStore {
+	return &MemoryStore{store: make(map[interface{}]interface{})}
+}
+
+func (s *MemoryStore) Put(key, value interface{}) error {
+	s.mutex.Lock()
+	defer s.mutex.Unlock()
+	s.store[key] = value
+	//fmt.Println("after put store:", s.store)
+	return nil
+}
+
+func (s *MemoryStore) Get(key interface{}) (interface{}, error) {
+	s.mutex.Lock()
+	defer s.mutex.Unlock()
+	//fmt.Println("before get store:", s.store)
+	if v, ok := s.store[key]; ok {
+		return v, nil
+	}
+
+	return nil, ErrNotExist
+}
+
+func (s *MemoryStore) Del(key interface{}) error {
+	s.mutex.Lock()
+	defer s.mutex.Unlock()
+	//fmt.Println("before del store:", s.store)
+	delete(s.store, key)
+	//fmt.Println("after del store:", s.store)
+	return nil
+}
+
+type Cacher interface {
+	Get(id interface{}) interface{}
+	Put(id, obj interface{})
+	Del(id interface{})
+}
+
+// LRUCacher implements Cacher according to LRU algorithm
+type LRUCacher struct {
+	name  string
+	list  *list.List
+	index map[interface{}]*list.Element
+	store CacheStore
+	Max   int
+	mutex sync.RWMutex
+}
+
+func NewLRUCacher(store CacheStore, max int) *LRUCacher {
+	return &LRUCacher{store: store, list: list.New(),
+		index: make(map[interface{}]*list.Element), Max: max}
+}
+
+func (m *LRUCacher) Get(id interface{}) interface{} {
+	m.mutex.RLock()
+	defer m.mutex.RUnlock()
+	if v, err := m.store.Get(id); err == nil {
+		el := m.index[id]
+		m.list.MoveToBack(el)
+		return v
+	}
+	return nil
+}
+
+func (m *LRUCacher) Put(id interface{}, obj interface{}) {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+	el := m.list.PushBack(id)
+	m.index[id] = el
+	m.store.Put(id, obj)
+	if m.list.Len() > m.Max {
+		e := m.list.Front()
+		m.store.Del(e.Value)
+		delete(m.index, e.Value)
+		m.list.Remove(e)
+	}
+}
+
+func (m *LRUCacher) Del(id interface{}) {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+	if el, ok := m.index[id]; ok {
+		m.store.Del(id)
+		delete(m.index, el.Value)
+		m.list.Remove(el)
+	}
+}
+
+func encodeIds(ids []int64) (s string) {
+	s = "["
+	for _, id := range ids {
+		s += fmt.Sprintf("%v,", id)
+	}
+	s = s[:len(s)-1] + "]"
+	return
+}
+
+func decodeIds(s string) []int64 {
+	res := make([]int64, 0)
+	if len(s) >= 2 {
+		ss := strings.Split(s[1:len(s)-1], ",")
+		for _, s := range ss {
+			i, err := strconv.ParseInt(s, 10, 64)
+			if err != nil {
+				return res
+			}
+			res = append(res, i)
+		}
+	}
+	return res
+}
+
+func GetCacheSql(m Cacher, sql string) ([]int64, error) {
+	bytes := m.Get(sql)
+	if bytes == nil {
+		return nil, errors.New("Not Exist")
+	}
+	objs := decodeIds(bytes.(string))
+	return objs, nil
+}
+
+func PutCacheSql(m Cacher, sql string, ids []int64) error {
+	bytes := encodeIds(ids)
+	m.Put(sql, bytes)
+	return nil
+}
+
+func DelCacheSql(m Cacher, sql string) error {
+	m.Del(sql)
+	return nil
+}
+
+func genId(prefix string, id int64) string {
+	return fmt.Sprintf("%v-%v", prefix, id)
+}
+
+func GetCacheId(m Cacher, prefix string, id int64) interface{} {
+	return m.Get(genId(prefix, id))
+}
+
+func PutCacheId(m Cacher, prefix string, id int64, bean interface{}) error {
+	m.Put(genId(prefix, id), bean)
+	return nil
+}
+
+func DelCacheId(m Cacher, prefix string, id int64) error {
+	m.Del(genId(prefix, id))
+	//TODO: should delete id from select
+	return nil
+}
diff --git a/engine.go b/engine.go
index 9a2ea09a..a7497f09 100644
--- a/engine.go
+++ b/engine.go
@@ -36,9 +36,10 @@ type Engine struct {
 	mutex          *sync.Mutex
 	ShowSQL        bool
 	Pool           IConnectPool
-	CacheMapping   bool
 	Filters        []Filter
 	Logger         io.Writer
+	Cacher         Cacher
+	UseCache       bool
 }
 
 func (engine *Engine) SupportInsertMany() bool {
@@ -70,6 +71,25 @@ func (engine *Engine) SetMaxConns(conns int) {
 	engine.Pool.SetMaxConns(conns)
 }
 
+func (engine *Engine) SetDefaultCacher(cacher Cacher) {
+	if cacher == nil {
+		engine.UseCache = false
+	} else {
+		engine.UseCache = true
+		engine.Cacher = cacher
+	}
+}
+
+func (engine *Engine) NoCache(bean interface{}) {
+	engine.MapCacher(bean, nil)
+}
+
+func (engine *Engine) MapCacher(bean interface{}, cacher Cacher) {
+	t := Type(bean)
+	engine.AutoMapType(t)
+	engine.Tables[t].Cacher = cacher
+}
+
 func Type(bean interface{}) reflect.Type {
 	sliceValue := reflect.Indirect(reflect.ValueOf(bean))
 	return reflect.TypeOf(sliceValue.Interface())
@@ -119,6 +139,12 @@ func (engine *Engine) Sql(querystring string, args ...interface{}) *Session {
 	return session.Sql(querystring, args...)
 }
 
+func (engine *Engine) NoAutoTime() *Session {
+	session := engine.NewSession()
+	session.IsAutoClose = true
+	return session.NoAutoTime()
+}
+
 func (engine *Engine) Cascade(trueOrFalse ...bool) *Session {
 	session := engine.NewSession()
 	session.IsAutoClose = true
@@ -155,11 +181,11 @@ func (engine *Engine) Cols(columns ...string) *Session {
 	return session.Cols(columns...)
 }
 
-func (engine *Engine) Trans(t string) *Session {
+/*func (engine *Engine) Trans(t string) *Session {
 	session := engine.NewSession()
 	session.IsAutoClose = true
 	return session.Trans(t)
-}
+}*/
 
 func (engine *Engine) In(column string, args ...interface{}) *Session {
 	session := engine.NewSession()
@@ -233,8 +259,16 @@ func (engine *Engine) AutoMap(bean interface{}) *Table {
 	return engine.AutoMapType(t)
 }
 
+func (engine *Engine) newTable() *Table {
+	table := &Table{Indexes: map[string][]string{}, Uniques: map[string][]string{}}
+	table.Columns = make(map[string]*Column)
+	table.ColumnsSeq = make([]string, 0)
+	table.Cacher = engine.Cacher
+	return table
+}
+
 func (engine *Engine) MapType(t reflect.Type) *Table {
-	table := NewTable()
+	table := engine.newTable()
 	table.Name = engine.Mapper.Obj2Table(t.Name())
 	table.Type = t
 
diff --git a/error.go b/error.go
index b275d26b..03520655 100644
--- a/error.go
+++ b/error.go
@@ -9,4 +9,5 @@ var (
 	ErrTableNotFound   error = errors.New("not found table")
 	ErrUnSupportedType error = errors.New("unsupported type error")
 	ErrNotExist        error = errors.New("not exist error")
+	ErrCacheFailed     error = errors.New("cache failed")
 )
diff --git a/examples/cache.go b/examples/cache.go
new file mode 100644
index 00000000..134386ce
--- /dev/null
+++ b/examples/cache.go
@@ -0,0 +1,107 @@
+package main
+
+import (
+	"fmt"
+	_ "github.com/mattn/go-sqlite3"
+	"os"
+	. "xorm"
+)
+
+type User struct {
+	Id   int64
+	Name string
+}
+
+func main() {
+	f := "cache.db"
+	os.Remove(f)
+
+	Orm, err := NewEngine("sqlite3", f)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	Orm.ShowSQL = true
+	cacher := NewLRUCacher(NewMemoryStore(), 1000)
+	Orm.SetDefaultCacher(cacher)
+
+	err = Orm.CreateTables(&User{})
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	_, err = Orm.Insert(&User{Name: "xlw"})
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	users := make([]User, 0)
+	err = Orm.Find(&users)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	fmt.Println("users:", users)
+
+	users2 := make([]User, 0)
+
+	err = Orm.Find(&users2)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	fmt.Println("users2:", users2)
+
+	users3 := make([]User, 0)
+
+	err = Orm.Find(&users3)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	fmt.Println("users3:", users3)
+
+	user4 := new(User)
+	has, err := Orm.Id(1).Get(user4)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	fmt.Println("user4:", has, user4)
+
+	user4.Name = "xiaolunwen"
+	_, err = Orm.Id(1).Update(user4)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	fmt.Println("user4:", user4)
+
+	user5 := new(User)
+	has, err = Orm.Id(1).Get(user5)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	fmt.Println("user5:", has, user5)
+
+	_, err = Orm.Id(1).Delete(new(User))
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	user6 := new(User)
+	has, err = Orm.Id(1).Get(user6)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	fmt.Println("user6:", has, user6)
+}
diff --git a/examples/cachegoroutine.go b/examples/cachegoroutine.go
new file mode 100644
index 00000000..af3c62b9
--- /dev/null
+++ b/examples/cachegoroutine.go
@@ -0,0 +1,112 @@
+package main
+
+import (
+	//xorm "github.com/lunny/xorm"
+	"fmt"
+	_ "github.com/go-sql-driver/mysql"
+	_ "github.com/mattn/go-sqlite3"
+	"os"
+	//"time"
+	//"sync/atomic"
+	xorm "xorm"
+)
+
+type User struct {
+	Id   int64
+	Name string
+}
+
+func sqliteEngine() (*xorm.Engine, error) {
+	os.Remove("./test.db")
+	return xorm.NewEngine("sqlite3", "./goroutine.db")
+}
+
+func mysqlEngine() (*xorm.Engine, error) {
+	return xorm.NewEngine("mysql", "root:@/test?charset=utf8")
+}
+
+var u *User = &User{}
+
+func test(engine *xorm.Engine) {
+	err := engine.CreateTables(u)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	size := 500
+	queue := make(chan int, size)
+
+	for i := 0; i < size; i++ {
+		go func(x int) {
+			//x := i
+			err := engine.Test()
+			if err != nil {
+				fmt.Println(err)
+			} else {
+				err = engine.Map(u)
+				if err != nil {
+					fmt.Println("Map user failed")
+				} else {
+					for j := 0; j < 10; j++ {
+						if x+j < 2 {
+							_, err = engine.Get(u)
+						} else if x+j < 4 {
+							users := make([]User, 0)
+							err = engine.Find(&users)
+						} else if x+j < 8 {
+							_, err = engine.Count(u)
+						} else if x+j < 16 {
+							_, err = engine.Insert(&User{Name: "xlw"})
+						} else if x+j < 32 {
+							_, err = engine.Id(1).Delete(u)
+						}
+						if err != nil {
+							fmt.Println(err)
+							queue <- x
+							return
+						}
+					}
+					fmt.Printf("%v success!\n", x)
+				}
+			}
+			queue <- x
+		}(i)
+	}
+
+	for i := 0; i < size; i++ {
+		<-queue
+	}
+
+	//conns := atomic.LoadInt32(&xorm.ConnectionNum)
+	//fmt.Println("connection number:", conns)
+	fmt.Println("end")
+}
+
+func main() {
+	fmt.Println("-----start sqlite go routines-----")
+	engine, err := sqliteEngine()
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	engine.ShowSQL = true
+	cacher := xorm.NewLRUCacher(xorm.NewMemoryStore(), 1000)
+	engine.SetDefaultCacher(cacher)
+	fmt.Println(engine)
+	test(engine)
+	fmt.Println("test end")
+	engine.Close()
+
+	fmt.Println("-----start mysql go routines-----")
+	engine, err = mysqlEngine()
+	engine.ShowSQL = true
+	cacher = xorm.NewLRUCacher(xorm.NewMemoryStore(), 1000)
+	engine.SetDefaultCacher(cacher)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	defer engine.Close()
+	test(engine)
+}
diff --git a/examples/maxconnect.go b/examples/maxconnect.go
index bb979298..b930abca 100644
--- a/examples/maxconnect.go
+++ b/examples/maxconnect.go
@@ -95,7 +95,7 @@ func main() {
 	engine.ShowSQL = true
 	fmt.Println(engine)
 	test(engine)
-	fmt.Println("test end")
+	fmt.Println("------------------------")
 	engine.Close()
 
 	engine, err = mysqlEngine()
diff --git a/pool.go b/pool.go
index 21bda9af..ea88af11 100644
--- a/pool.go
+++ b/pool.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"sync"
 	//"sync/atomic"
+	"container/list"
 	"time"
 )
 
@@ -81,8 +82,7 @@ type SysConnectPool struct {
 	maxConns     int
 	curConns     int
 	mutex        *sync.Mutex
-	condMutex    *sync.Mutex
-	cond         *sync.Cond
+	queue        *list.List
 }
 
 // NewSysConnectPool new a SysConnectPool.
@@ -101,43 +101,61 @@ func (s *SysConnectPool) Init(engine *Engine) error {
 	s.maxConns = -1
 	s.curConns = 0
 	s.mutex = &sync.Mutex{}
-	s.condMutex = &sync.Mutex{}
-	s.cond = sync.NewCond(s.condMutex)
+	s.queue = list.New()
 	return nil
 }
 
+type node struct {
+	mutex sync.Mutex
+	cond  *sync.Cond
+}
+
+func NewNode() *node {
+	n := &node{}
+	n.cond = sync.NewCond(&n.mutex)
+	return n
+}
+
 // RetrieveDB just return the only db
-func (p *SysConnectPool) RetrieveDB(engine *Engine) (db *sql.DB, err error) {
-	if p.maxConns > 0 {
-		p.condMutex.Lock()
-		fmt.Println("before retrieve - current connections:", p.curConns, p.maxConns)
-		for p.curConns >= p.maxConns {
-			fmt.Println("waiting...", p.curConns)
-			p.cond.Wait()
+func (s *SysConnectPool) RetrieveDB(engine *Engine) (db *sql.DB, err error) {
+	if s.maxConns > 0 {
+		fmt.Println("before retrieve")
+		s.mutex.Lock()
+		for s.curConns >= s.maxConns {
+			fmt.Println("before waiting...", s.curConns, s.queue.Len())
+			s.mutex.Unlock()
+			n := NewNode()
+			n.cond.L.Lock()
+			s.queue.PushBack(n)
+			n.cond.Wait()
+			n.cond.L.Unlock()
+			s.mutex.Lock()
+			fmt.Println("after waiting...", s.curConns, s.queue.Len())
 		}
-		//p.mutex.Lock()
-		p.curConns += 1
-		p.cond.Signal()
-		//p.mutex.Lock()
-		p.condMutex.Unlock()
+		s.curConns += 1
+		s.mutex.Unlock()
+		fmt.Println("after retrieve")
 	}
-	return p.db, nil
+	return s.db, nil
 }
 
 // ReleaseDB do nothing
-func (p *SysConnectPool) ReleaseDB(engine *Engine, db *sql.DB) {
-	if p.maxConns > 0 {
-		p.condMutex.Lock()
-		fmt.Println("before release - current connections:", p.curConns, p.maxConns)
-		//if p.curConns >= p.maxConns-2 {
-		fmt.Println("signaling...")
-		//p.mutex.Lock()
-		p.curConns -= 1
-		//p.mutex.Unlock()
-		p.cond.Signal()
-		//}
-		p.condMutex.Unlock()
+func (s *SysConnectPool) ReleaseDB(engine *Engine, db *sql.DB) {
+	if s.maxConns > 0 {
+		s.mutex.Lock()
+		fmt.Println("before release", s.queue.Len())
+		s.curConns -= 1
 
+		if e := s.queue.Front(); e != nil {
+			n := e.Value.(*node)
+			//n.cond.L.Lock()
+			n.cond.Signal()
+			fmt.Println("signaled...")
+			s.queue.Remove(e)
+			//n.cond.L.Unlock()
+		}
+		fmt.Println("after released", s.queue.Len())
+		s.mutex.Unlock()
 	}
 }
 
diff --git a/session.go b/session.go
index b8c094e9..6234e14a 100644
--- a/session.go
+++ b/session.go
@@ -71,11 +71,16 @@ func (session *Session) Cols(columns ...string) *Session {
 	return session
 }
 
-func (session *Session) Trans(t string) *Session {
-	session.TransType = t
+func (session *Session) NoAutoTime() *Session {
+	session.Statement.UseAutoTime = false
 	return session
 }
 
+/*func (session *Session) Trans(t string) *Session {
+	session.TransType = t
+	return session
+}*/
+
 func (session *Session) Limit(limit int, start ...int) *Session {
 	session.Statement.Limit(limit, start...)
 	return session
@@ -121,6 +126,11 @@ func (session *Session) Cascade(trueOrFalse ...bool) *Session {
 	return session
 }
 
+func (session *Session) NoCache() *Session {
+	session.Statement.UseCache = false
+	return session
+}
+
 //The join_operator should be one of INNER, LEFT OUTER, CROSS etc - this will be prepended to JOIN
 func (session *Session) Join(join_operator, tablename, condition string) *Session {
 	session.Statement.Join(join_operator, tablename, condition)
@@ -240,12 +250,7 @@ func (session *Session) innerExec(sql string, args ...interface{}) (sql.Result,
 	return res, nil
 }
 
-func (session *Session) Exec(sql string, args ...interface{}) (sql.Result, error) {
-	err := session.newDb()
-	if err != nil {
-		return nil, err
-	}
-
+func (session *Session) exec(sql string, args ...interface{}) (sql.Result, error) {
 	for _, filter := range session.Engine.Filters {
 		sql = filter.Do(sql, session)
 	}
@@ -259,6 +264,19 @@ func (session *Session) Exec(sql string, args ...interface{}) (sql.Result, error
 	return session.Tx.Exec(sql, args...)
 }
 
+func (session *Session) Exec(sql string, args ...interface{}) (sql.Result, error) {
+	err := session.newDb()
+	if err != nil {
+		return nil, err
+	}
+	defer session.Statement.Init()
+	if session.IsAutoClose {
+		defer session.Close()
+	}
+
+	return session.exec(sql, args...)
+}
+
 // this function create a table according a bean
 func (session *Session) CreateTable(bean interface{}) error {
 	session.Statement.RefTable = session.Engine.AutoMap(bean)
@@ -267,17 +285,21 @@ func (session *Session) CreateTable(bean interface{}) error {
 	if err != nil {
 		return err
 	}
+	defer session.Statement.Init()
+	if session.IsAutoClose {
+		defer session.Close()
+	}
 
 	return session.createOneTable()
 }
 
 func (session *Session) createOneTable() error {
 	sql := session.Statement.genCreateSQL()
-	_, err := session.Exec(sql)
+	_, err := session.exec(sql)
 	if err == nil {
 		sqls := session.Statement.genIndexSQL()
 		for _, sql := range sqls {
-			_, err = session.Exec(sql)
+			_, err = session.exec(sql)
 			if err != nil {
 				return err
 			}
@@ -286,7 +308,7 @@ func (session *Session) createOneTable() error {
 	if err == nil {
 		sqls := session.Statement.genUniqueSQL()
 		for _, sql := range sqls {
-			_, err = session.Exec(sql)
+			_, err = session.exec(sql)
 			if err != nil {
 				return err
 			}
@@ -300,7 +322,7 @@ func (session *Session) CreateAll() error {
 	if err != nil {
 		return err
 	}
-
+	defer session.Statement.Init()
 	if session.IsAutoClose {
 		defer session.Close()
 	}
@@ -321,6 +343,7 @@ func (session *Session) DropTable(bean interface{}) error {
 		return err
 	}
 
+	defer session.Statement.Init()
 	if session.IsAutoClose {
 		defer session.Close()
 	}
@@ -336,33 +359,227 @@ func (session *Session) DropTable(bean interface{}) error {
 	}
 
 	sql := session.Statement.genDropSQL()
-	_, err = session.Exec(sql)
+	_, err = session.exec(sql)
 	return err
 }
 
+func (statement *Statement) convertIdSql(sql string) string {
+	if statement.RefTable != nil {
+		col := statement.RefTable.PKColumn()
+		if col != nil {
+			sql = strings.ToLower(sql)
+			sqls := strings.SplitN(sql, "from", 2)
+			if len(sqls) != 2 {
+				return ""
+			}
+			return fmt.Sprintf("SELECT %v FROM %v", statement.Engine.Quote(col.Name), sqls[1])
+		}
+	}
+	return ""
+}
+
+func (session *Session) cacheGet(bean interface{}, sql string, args ...interface{}) (has bool, err error) {
+	if session.Statement.RefTable == nil || session.Statement.RefTable.PrimaryKey == "" {
+		return false, ErrCacheFailed
+	}
+	for _, filter := range session.Engine.Filters {
+		sql = filter.Do(sql, session)
+	}
+	newsql := session.Statement.convertIdSql(sql)
+	if newsql == "" {
+		return false, ErrCacheFailed
+	}
+
+	cacher := session.Statement.RefTable.Cacher
+	ids, err := GetCacheSql(cacher, newsql)
+	if err != nil {
+		fmt.Println(err)
+		resultsSlice, err := session.query(newsql, args...)
+		if err != nil {
+			return false, err
+		}
+
+		ids = make([]int64, 0)
+		if len(resultsSlice) > 0 {
+			data := resultsSlice[0]
+			//fmt.Println(data)
+			var id int64
+			if v, ok := data[session.Statement.RefTable.PrimaryKey]; !ok {
+				return false, errors.New("no id")
+			} else {
+				id, err = strconv.ParseInt(string(v), 10, 64)
+				if err != nil {
+					return false, err
+				}
+			}
+			ids = append(ids, id)
+		}
+		err = PutCacheSql(cacher, newsql, ids)
+		if err != nil {
+			fmt.Println(err)
+		}
+	} else {
+		fmt.Printf("-----Cached SQL: %v.\n", newsql)
+	}
+
+	structValue := reflect.Indirect(reflect.ValueOf(bean))
+	//fmt.Println("xxxxxxx", ids)
+	if len(ids) > 0 {
+		id := ids[0]
+		tableName := session.Statement.TableName()
+		bean = GetCacheId(cacher, tableName, id)
+		if bean == nil {
+			fmt.Printf("----Object Id %v no cached.\n", id)
+			newSession := session.Engine.NewSession()
+			defer newSession.Close()
+			bean = reflect.New(structValue.Type()).Interface()
+			has, err = newSession.Id(id).NoCache().Get(bean)
+			if err != nil {
+				return has, err
+			}
+			//fmt.Println(bean)
+			PutCacheId(cacher, tableName, id, bean)
+		} else {
+			fmt.Printf("-----Cached Object: %v\n", bean)
+			has = true
+		}
+
+		structValue.Set(reflect.ValueOf(bean).Elem())
+		return has, nil
+	}
+	return false, nil
+}
+
+func (session *Session) cacheFind(t reflect.Type, sql string, rowsSlicePtr interface{}, args ...interface{}) (err error) {
+	if session.Statement.RefTable == nil || session.Statement.RefTable.PrimaryKey == "" {
+		return ErrCacheFailed
+	}
+
+	for _, filter := range session.Engine.Filters {
+		sql = filter.Do(sql, session)
+	}
+
+	newsql := session.Statement.convertIdSql(sql)
+	if newsql == "" {
+		return ErrCacheFailed
+	}
+
+	table := session.Statement.RefTable
+	cacher := table.Cacher
+	ids, err := GetCacheSql(cacher, newsql)
+	if err != nil {
+		fmt.Println(err)
+		resultsSlice, err := session.query(newsql, args...)
+		if err != nil {
+			return err
+		}
+		// 查询数目太大，采用缓存将不是一个很好的方式。
+		if len(resultsSlice) > 20 {
+			return ErrCacheFailed
+		}
+		ids = make([]int64, 0)
+		if len(resultsSlice) > 0 {
+			for _, data := range resultsSlice {
+				//fmt.Println(data)
+				var id int64
+				if v, ok := data[session.Statement.RefTable.PrimaryKey]; !ok {
+					return errors.New("no id")
+				} else {
+					id, err = strconv.ParseInt(string(v), 10, 64)
+					if err != nil {
+						return err
+					}
+				}
+				ids = append(ids, id)
+			}
+		}
+		err = PutCacheSql(cacher, newsql, ids)
+		if err != nil {
+			fmt.Println(err)
+		}
+	} else {
+		fmt.Printf("-----Cached SQL: %v.\n", newsql)
+	}
+
+	sliceValue := reflect.Indirect(reflect.ValueOf(rowsSlicePtr))
+	//fmt.Println("xxxxxxx", ids)
+	var idxes []int = make([]int, 0)
+	var ides []interface{} = make([]interface{}, 0)
+	var temps []interface{} = make([]interface{}, len(ids))
+	for idx, id := range ids {
+		tableName := session.Statement.TableName()
+		bean := GetCacheId(cacher, tableName, id)
+		if bean == nil {
+			fmt.Printf("----Object Id %v no cached.\n", id)
+			idxes = append(idxes, idx)
+			ides = append(ides, id)
+			/*newSession := session.Engine.NewSession()
+			defer newSession.Close()
+			bean = reflect.New(t).Interface()
+			_, err = newSession.Id(id).In(, ...).NoCache().Get(bean)
+			if err != nil {
+				return err
+			}
+
+			PutCacheId(cacher, tableName, id, bean)*/
+		} else {
+			fmt.Printf("-----Cached Object: %v\n", bean)
+			temps[idx] = bean
+		}
+
+		//sliceValue.Set(reflect.Append(sliceValue, reflect.ValueOf(bean).Elem()))
+	}
+
+	newSession := session.Engine.NewSession()
+	defer newSession.Close()
+
+	beans := reflect.New(sliceValue.Type()).Interface()
+	err = newSession.In("(id)", ides...).OrderBy(session.Statement.OrderStr).NoCache().Find(beans)
+	if err != nil {
+		return err
+	}
+
+	vs := reflect.Indirect(reflect.ValueOf(beans))
+	for i := 0; i < vs.Len(); i++ {
+		temps[idxes[i]] = vs.Index(i).Interface()
+	}
+
+	//sliceValue.SetPointer(x)
+
+	return nil
+}
+
+// get retrieve one record from database
 func (session *Session) Get(bean interface{}) (bool, error) {
 	err := session.newDb()
 	if err != nil {
 		return false, err
 	}
 
+	defer session.Statement.Init()
 	if session.IsAutoClose {
 		defer session.Close()
 	}
 
-	defer session.Statement.Init()
 	session.Statement.Limit(1)
 	var sql string
 	var args []interface{}
+	session.Statement.RefTable = session.Engine.AutoMap(bean)
 	if session.Statement.RawSQL == "" {
 		sql, args = session.Statement.genGetSql(bean)
 	} else {
 		sql = session.Statement.RawSQL
 		args = session.Statement.RawParams
-		session.Engine.AutoMap(bean)
 	}
 
-	resultsSlice, err := session.Query(sql, args...)
+	if session.Statement.RefTable.Cacher != nil && session.Statement.UseCache {
+		has, err := session.cacheGet(bean, sql, args...)
+		if err != ErrCacheFailed {
+			return has, err
+		}
+	}
+
+	resultsSlice, err := session.query(sql, args...)
 	if err != nil {
 		return false, err
 	}
@@ -390,11 +607,11 @@ func (session *Session) Count(bean interface{}) (int64, error) {
 		return 0, err
 	}
 
+	defer session.Statement.Init()
 	if session.IsAutoClose {
 		defer session.Close()
 	}
 
-	defer session.Statement.Init()
 	var sql string
 	var args []interface{}
 	if session.Statement.RawSQL == "" {
@@ -404,7 +621,7 @@ func (session *Session) Count(bean interface{}) (int64, error) {
 		args = session.Statement.RawParams
 	}
 
-	resultsSlice, err := session.Query(sql, args...)
+	resultsSlice, err := session.query(sql, args...)
 	if err != nil {
 		return 0, err
 	}
@@ -426,12 +643,11 @@ func (session *Session) Find(rowsSlicePtr interface{}, condiBean ...interface{})
 	if err != nil {
 		return err
 	}
-
+	defer session.Statement.Init()
 	if session.IsAutoClose {
 		defer session.Close()
 	}
 
-	defer session.Statement.Init()
 	sliceValue := reflect.Indirect(reflect.ValueOf(rowsSlicePtr))
 	if sliceValue.Kind() != reflect.Slice && sliceValue.Kind() != reflect.Map {
 		return errors.New("needs a pointer to a slice or a map")
@@ -461,8 +677,14 @@ func (session *Session) Find(rowsSlicePtr interface{}, condiBean ...interface{})
 		args = session.Statement.RawParams
 	}
 
-	resultsSlice, err := session.Query(sql, args...)
+	if table.Cacher != nil && session.Statement.UseCache {
+		err = session.cacheFind(sliceElementType, sql, rowsSlicePtr, args...)
+		if err != ErrCacheFailed {
+			return err
+		}
+	}
 
+	resultsSlice, err := session.query(sql, args...)
 	if err != nil {
 		return err
 	}
@@ -497,7 +719,7 @@ func (session *Session) Ping() error {
 	if err != nil {
 		return err
 	}
-
+	defer session.Statement.Init()
 	if session.IsAutoClose {
 		defer session.Close()
 	}
@@ -510,7 +732,7 @@ func (session *Session) DropAll() error {
 	if err != nil {
 		return err
 	}
-
+	defer session.Statement.Init()
 	if session.IsAutoClose {
 		defer session.Close()
 	}
@@ -519,7 +741,7 @@ func (session *Session) DropAll() error {
 		session.Statement.Init()
 		session.Statement.RefTable = table
 		sql := session.Statement.genDropSQL()
-		_, err := session.Exec(sql)
+		_, err := session.exec(sql)
 		if err != nil {
 			return err
 		}
@@ -527,16 +749,7 @@ func (session *Session) DropAll() error {
 	return nil
 }
 
-func (session *Session) Query(sql string, paramStr ...interface{}) (resultsSlice []map[string][]byte, err error) {
-	err = session.newDb()
-	if err != nil {
-		return nil, err
-	}
-
-	if session.IsAutoClose {
-		defer session.Close()
-	}
-
+func (session *Session) query(sql string, paramStr ...interface{}) (resultsSlice []map[string][]byte, err error) {
 	for _, filter := range session.Engine.Filters {
 		sql = filter.Do(sql, session)
 	}
@@ -616,19 +829,28 @@ func (session *Session) Query(sql string, paramStr ...interface{}) (resultsSlice
 	return resultsSlice, nil
 }
 
+func (session *Session) Query(sql string, paramStr ...interface{}) (resultsSlice []map[string][]byte, err error) {
+	err = session.newDb()
+	if err != nil {
+		return nil, err
+	}
+	defer session.Statement.Init()
+	if session.IsAutoClose {
+		defer session.Close()
+	}
+
+	return session.query(sql, paramStr...)
+}
+
+// insert one or more beans
 func (session *Session) Insert(beans ...interface{}) (int64, error) {
 	var lastId int64 = -1
 	var err error = nil
-	isInTransaction := !session.IsAutoCommit
-
-	if !isInTransaction {
-		err = session.Begin()
-		//defer session.Close()
-		if err != nil {
-			return 0, err
-		}
+	err = session.newDb()
+	if err != nil {
+		return 0, err
 	}
-
+	defer session.Statement.Init()
 	if session.IsAutoClose {
 		defer session.Close()
 	}
@@ -639,13 +861,6 @@ func (session *Session) Insert(beans ...interface{}) (int64, error) {
 			if session.Engine.SupportInsertMany() {
 				lastId, err = session.innerInsertMulti(bean)
 				if err != nil {
-					if !isInTransaction {
-						err1 := session.Rollback()
-						if err1 == nil {
-							return lastId, err
-						}
-						err = err1
-					}
 					return lastId, err
 				}
 			} else {
@@ -653,13 +868,6 @@ func (session *Session) Insert(beans ...interface{}) (int64, error) {
 				for i := 0; i < size; i++ {
 					lastId, err = session.innerInsert(sliceValue.Index(i).Interface())
 					if err != nil {
-						if !isInTransaction {
-							err1 := session.Rollback()
-							if err1 == nil {
-								return lastId, err
-							}
-							err = err1
-						}
 						return lastId, err
 					}
 				}
@@ -667,20 +875,11 @@ func (session *Session) Insert(beans ...interface{}) (int64, error) {
 		} else {
 			lastId, err = session.innerInsert(bean)
 			if err != nil {
-				if !isInTransaction {
-					err1 := session.Rollback()
-					if err1 == nil {
-						return lastId, err
-					}
-					err = err1
-				}
 				return lastId, err
 			}
 		}
 	}
-	if !isInTransaction {
-		err = session.Commit()
-	}
+
 	return lastId, err
 }
 
@@ -721,7 +920,7 @@ func (session *Session) innerInsertMulti(rowsSlicePtr interface{}) (int64, error
 						continue
 					}
 				}
-				if col.IsCreated || col.IsUpdated {
+				if (col.IsCreated || col.IsUpdated) && session.Statement.UseAutoTime {
 					args = append(args, time.Now())
 				} else {
 					arg, err := session.value2Interface(col, fieldValue)
@@ -749,7 +948,7 @@ func (session *Session) innerInsertMulti(rowsSlicePtr interface{}) (int64, error
 						continue
 					}
 				}
-				if col.IsCreated || col.IsUpdated {
+				if (col.IsCreated || col.IsUpdated) && session.Statement.UseAutoTime {
 					args = append(args, time.Now())
 				} else {
 					arg, err := session.value2Interface(col, fieldValue)
@@ -774,7 +973,7 @@ func (session *Session) innerInsertMulti(rowsSlicePtr interface{}) (int64, error
 		session.Engine.QuoteStr(),
 		strings.Join(colMultiPlaces, "),("))
 
-	res, err := session.Exec(statement, args...)
+	res, err := session.exec(statement, args...)
 	if err != nil {
 		return -1, err
 	}
@@ -790,13 +989,13 @@ func (session *Session) innerInsertMulti(rowsSlicePtr interface{}) (int64, error
 
 func (session *Session) InsertMulti(rowsSlicePtr interface{}) (int64, error) {
 	err := session.newDb()
-	if session.IsAutoClose {
-		defer session.Close()
-	}
-
 	if err != nil {
 		return 0, err
 	}
+	defer session.Statement.Init()
+	if session.IsAutoClose {
+		defer session.Close()
+	}
 
 	return session.innerInsertMulti(rowsSlicePtr)
 }
@@ -1024,7 +1223,7 @@ func (session *Session) innerInsert(bean interface{}) (int64, error) {
 			}
 		}
 
-		if col.IsCreated || col.IsUpdated {
+		if (col.IsCreated || col.IsUpdated) && session.Statement.UseAutoTime {
 			args = append(args, time.Now())
 		} else {
 			arg, err := session.value2Interface(col, fieldValue)
@@ -1047,7 +1246,7 @@ func (session *Session) innerInsert(bean interface{}) (int64, error) {
 		session.Engine.QuoteStr(),
 		strings.Join(colPlaces, ", "))
 
-	res, err := session.Exec(sql, args...)
+	res, err := session.exec(sql, args...)
 	if err != nil {
 		return 0, err
 	}
@@ -1081,32 +1280,134 @@ func (session *Session) innerInsert(bean interface{}) (int64, error) {
 
 func (session *Session) InsertOne(bean interface{}) (int64, error) {
 	err := session.newDb()
-	if session.IsAutoClose {
-		defer session.Close()
-	}
 	if err != nil {
 		return 0, err
 	}
+	defer session.Statement.Init()
+	if session.IsAutoClose {
+		defer session.Close()
+	}
 
 	return session.innerInsert(bean)
 }
 
+func (statement *Statement) convertUpdateSql(sql string) (string, string) {
+	if statement.RefTable == nil || statement.RefTable.PrimaryKey == "" {
+		return "", ""
+	}
+	sqls := strings.SplitN(strings.ToLower(sql), "where", 2)
+	if len(sqls) != 2 {
+		return "", ""
+	}
+
+	return sqls[0], fmt.Sprintf("SELECT %v FROM %v WHERE %v",
+		statement.Engine.Quote(statement.RefTable.PrimaryKey), statement.Engine.Quote(statement.TableName()),
+		sqls[1])
+}
+
+func (session *Session) cacheUpdate(sql string, args ...interface{}) error {
+	if session.Statement.RefTable == nil || session.Statement.RefTable.PrimaryKey == "" {
+		return ErrCacheFailed
+	}
+
+	for _, filter := range session.Engine.Filters {
+		sql = filter.Do(sql, session)
+	}
+
+	oldhead, newsql := session.Statement.convertUpdateSql(sql)
+	if newsql == "" {
+		return ErrCacheFailed
+	}
+
+	var nStart int
+	if len(args) > 0 {
+		if strings.Index(sql, "?") > -1 {
+			nStart = strings.Count(oldhead, "?")
+		} else {
+			// for pq, TODO: if any other databse?
+			nStart = strings.Count(oldhead, "$")
+		}
+	}
+	table := session.Statement.RefTable
+	cacher := table.Cacher
+	ids, err := GetCacheSql(cacher, newsql)
+	if err != nil {
+		resultsSlice, err := session.query(newsql, args[nStart:]...)
+		if err != nil {
+			return err
+		}
+		ids = make([]int64, 0)
+		if len(resultsSlice) > 0 {
+			for _, data := range resultsSlice {
+				var id int64
+				if v, ok := data[session.Statement.RefTable.PrimaryKey]; !ok {
+					return errors.New("no id")
+				} else {
+					id, err = strconv.ParseInt(string(v), 10, 64)
+					if err != nil {
+						return err
+					}
+				}
+				ids = append(ids, id)
+			}
+		}
+	} else {
+		fmt.Printf("-----Cached SQL: %v.\n", newsql)
+		DelCacheSql(cacher, newsql)
+	}
+
+	for _, id := range ids {
+		if bean := GetCacheId(cacher, session.Statement.TableName(), id); bean != nil {
+			sqls := strings.SplitN(strings.ToLower(sql), "where", 2)
+			if len(sqls) != 2 {
+				return nil
+			}
+			sqls = strings.SplitN(sqls[0], "set", 2)
+			if len(sqls) != 2 {
+				return nil
+			}
+			kvs := strings.Split(strings.TrimSpace(sqls[1]), ",")
+			for idx, kv := range kvs {
+				sps := strings.SplitN(kv, "=", 2)
+				sps2 := strings.Split(sps[0], ".")
+				colName := sps2[len(sps2)-1]
+				if strings.Contains(colName, "`") {
+					colName = strings.TrimSpace(strings.Replace(colName, "`", "", -1))
+				} else if strings.Contains(colName, session.Engine.QuoteStr()) {
+					colName = strings.TrimSpace(strings.Replace(colName, session.Engine.QuoteStr(), "", -1))
+				}
+				//fmt.Println("find", colName)
+				if col, ok := table.Columns[colName]; ok {
+					fieldValue := col.ValueOf(bean)
+					//session.bytes2Value(col, fieldValue, []byte(args[idx]))
+					fieldValue.Set(reflect.ValueOf(args[idx]))
+				}
+			}
+
+			PutCacheId(cacher, session.Statement.TableName(), id, bean)
+		}
+	}
+	return nil
+}
+
 func (session *Session) Update(bean interface{}, condiBean ...interface{}) (int64, error) {
 	err := session.newDb()
-	if session.IsAutoClose {
-		defer session.Close()
-	}
 	if err != nil {
 		return 0, err
 	}
+	defer session.Statement.Init()
+	if session.IsAutoClose {
+		defer session.Close()
+	}
 
 	t := Type(bean)
 
 	var colNames []string
 	var args []interface{}
+	var table *Table
 
 	if t.Kind() == reflect.Struct {
-		table := session.Engine.AutoMap(bean)
+		table = session.Engine.AutoMap(bean)
 		session.Statement.RefTable = table
 		colNames, args = BuildConditions(session.Engine, table, bean)
 		if table.Updated != "" {
@@ -1117,7 +1418,7 @@ func (session *Session) Update(bean interface{}, condiBean ...interface{}) (int6
 		if session.Statement.RefTable == nil {
 			return -1, ErrTableNotFound
 		}
-		table := session.Statement.RefTable
+		table = session.Statement.RefTable
 		colNames = make([]string, 0)
 		args = make([]interface{}, 0)
 		bValue := reflect.ValueOf(bean)
@@ -1163,38 +1464,84 @@ func (session *Session) Update(bean interface{}, condiBean ...interface{}) (int6
 		strings.Join(colNames, ", "),
 		condition)
 
-	eargs := append(append(args, st.Params...), condiArgs...)
-	res, err := session.Exec(sql, eargs...)
+	args = append(append(args, st.Params...), condiArgs...)
+
+	res, err := session.exec(sql, args...)
 	if err != nil {
-		return -1, err
+		return 0, err
 	}
 
-	rows, err := res.RowsAffected()
-
-	if err != nil {
-		return -1, err
+	if table.Cacher != nil && session.Statement.UseCache {
+		session.cacheUpdate(sql, args...)
 	}
-	return rows, nil
+
+	return res.RowsAffected()
+}
+
+func (session *Session) cacheDelete(sql string, args ...interface{}) error {
+	if session.Statement.RefTable == nil || session.Statement.RefTable.PrimaryKey == "" {
+		return ErrCacheFailed
+	}
+
+	for _, filter := range session.Engine.Filters {
+		sql = filter.Do(sql, session)
+	}
+
+	newsql := session.Statement.convertIdSql(sql)
+	if newsql == "" {
+		return ErrCacheFailed
+	}
+
+	cacher := session.Statement.RefTable.Cacher
+	ids, err := GetCacheSql(cacher, newsql)
+	if err != nil {
+		resultsSlice, err := session.query(newsql, args...)
+		if err != nil {
+			return err
+		}
+		ids = make([]int64, 0)
+		if len(resultsSlice) > 0 {
+			for _, data := range resultsSlice {
+				var id int64
+				if v, ok := data[session.Statement.RefTable.PrimaryKey]; !ok {
+					return errors.New("no id")
+				} else {
+					id, err = strconv.ParseInt(string(v), 10, 64)
+					if err != nil {
+						return err
+					}
+				}
+				ids = append(ids, id)
+			}
+		}
+	} else {
+		fmt.Printf("-----Cached SQL: %v.\n", newsql)
+		DelCacheSql(cacher, newsql)
+	}
+
+	for _, id := range ids {
+		DelCacheId(cacher, session.Statement.TableName(), id)
+	}
+	return nil
 }
 
 func (session *Session) Delete(bean interface{}) (int64, error) {
 	err := session.newDb()
-	if session.IsAutoClose {
-		defer session.Close()
-	}
 	if err != nil {
 		return 0, err
 	}
+	defer session.Statement.Init()
+	if session.IsAutoClose {
+		defer session.Close()
+	}
 
 	table := session.Engine.AutoMap(bean)
 	session.Statement.RefTable = table
 	colNames, args := BuildConditions(session.Engine, table, bean)
 
 	var condition = ""
-	st := session.Statement
-	defer session.Statement.Init()
-	if st.WhereStr != "" {
-		condition = fmt.Sprintf("WHERE %v", st.WhereStr)
+	if session.Statement.WhereStr != "" {
+		condition = fmt.Sprintf("WHERE %v", session.Statement.WhereStr)
 		if len(colNames) > 0 {
 			condition += " and "
 			condition += strings.Join(colNames, " and ")
@@ -1203,22 +1550,22 @@ func (session *Session) Delete(bean interface{}) (int64, error) {
 		condition = "WHERE " + strings.Join(colNames, " and ")
 	}
 
-	statement := fmt.Sprintf("DELETE FROM %v%v%v %v",
+	sql := fmt.Sprintf("DELETE FROM %v%v%v %v",
 		session.Engine.QuoteStr(),
 		session.Statement.TableName(),
 		session.Engine.QuoteStr(),
 		condition)
 
-	res, err := session.Exec(statement, append(st.Params, args...)...)
+	args = append(session.Statement.Params, args...)
 
-	if err != nil {
-		return -1, err
+	if table.Cacher != nil && session.Statement.UseCache {
+		session.cacheDelete(sql, args...)
 	}
 
-	id, err := res.RowsAffected()
-
+	res, err := session.exec(sql, args...)
 	if err != nil {
-		return -1, err
+		return 0, err
 	}
-	return id, nil
+
+	return res.RowsAffected()
 }
diff --git a/statement.go b/statement.go
index 2ef417e3..2343ccb6 100644
--- a/statement.go
+++ b/statement.go
@@ -31,6 +31,8 @@ type Statement struct {
 	StoreEngine  string
 	Charset      string
 	BeanArgs     []interface{}
+	UseCache     bool
+	UseAutoTime  bool
 }
 
 func MakeArray(elem string, count int) []string {
@@ -59,6 +61,8 @@ func (statement *Statement) Init() {
 	statement.RawSQL = ""
 	statement.RawParams = make([]interface{}, 0)
 	statement.BeanArgs = make([]interface{}, 0)
+	statement.UseCache = statement.Engine.UseCache
+	statement.UseAutoTime = true
 }
 
 func (statement *Statement) Sql(querystring string, args ...interface{}) {
diff --git a/table.go b/table.go
index b93dd075..f9316f24 100644
--- a/table.go
+++ b/table.go
@@ -232,6 +232,7 @@ type Table struct {
 	PrimaryKey string
 	Created    string
 	Updated    string
+	Cacher     Cacher
 }
 
 func (table *Table) PKColumn() *Column {
@@ -243,13 +244,6 @@ func (table *Table) AddColumn(col *Column) {
 	table.Columns[col.Name] = col
 }
 
-func NewTable() *Table {
-	table := &Table{Indexes: map[string][]string{}, Uniques: map[string][]string{}}
-	table.Columns = make(map[string]*Column)
-	table.ColumnsSeq = make([]string, 0)
-	return table
-}
-
 type Conversion interface {
 	FromDB([]byte) error
 	ToDB() ([]byte, error)
diff --git a/xorm.go b/xorm.go
index 3671a2b8..84859207 100644
--- a/xorm.go
+++ b/xorm.go
@@ -40,6 +40,7 @@ func NewEngine(driverName string, dataSourceName string) (*Engine, error) {
 
 	//engine.Pool = NewSimpleConnectPool()
 	//engine.Pool = NewNoneConnectPool()
+	//engine.Cacher = NewLRUCacher()
 	err := engine.SetPool(NewSysConnectPool())
 
 	return engine, err