700 lines
20 KiB
Markdown
700 lines
20 KiB
Markdown
Quick Start
|
||
=====
|
||
|
||
* [1.Create ORM Engine](#10)
|
||
* [2.Define a struct](#20)
|
||
* [2.1.Name mapping rule](#21)
|
||
* [2.2.Use Table or Tag to change table or column name](#22)
|
||
* [2.3.Column define](#23)
|
||
* [3. database schema operation](#30)
|
||
* [3.1.Retrieve database schema infomation](#31)
|
||
* [3.2.Table Operation](#32)
|
||
* [3.3.Create indexes and uniques](#33)
|
||
* [3.4.Sync database schema](#34)
|
||
* [4.Insert records](#40)
|
||
* [5.Query and Count records](#60)
|
||
* [5.1.Query condition methods](#61)
|
||
* [5.2.Temporory methods](#62)
|
||
* [5.3.Get](#63)
|
||
* [5.4.Find](#64)
|
||
* [5.5.Iterate](#65)
|
||
* [5.6.Count](#66)
|
||
* [6.Update records](#70)
|
||
* [6.1.Optimistic Locking](#71)
|
||
* [7.Delete records](#80)
|
||
* [8.Execute SQL command](#90)
|
||
* [9.Execute SQL query](#100)
|
||
* [10.Transaction](#110)
|
||
* [11.Cache](#120)
|
||
* [12.Xorm Tool](#130)
|
||
* [12.1.Reverse command](#131)
|
||
* [13.Examples](#140)
|
||
* [14.Cases](#150)
|
||
* [15.FAQ](#160)
|
||
* [16.Discuss](#170)
|
||
|
||
<a name="10" id="10"></a>
|
||
## 1.Create ORM Engine
|
||
|
||
When using xorm, you can create multiple orm engines, an engine means a databse. So you can：
|
||
|
||
```Go
|
||
import (
|
||
_ "github.com/go-sql-driver/mysql"
|
||
"github.com/go-xorm/xorm"
|
||
)
|
||
engine, err := xorm.NewEngine("mysql", "root:123@/test?charset=utf8")
|
||
defer engine.Close()
|
||
```
|
||
|
||
or
|
||
|
||
```Go
|
||
import (
|
||
_ "github.com/mattn/go-sqlite3"
|
||
"github.com/go-xorm/xorm"
|
||
)
|
||
engine, err = xorm.NewEngine("sqlite3", "./test.db")
|
||
defer engine.Close()
|
||
```
|
||
|
||
You can create many engines for different databases.Generally, you just need create only one engine. Engine supports run on go routines.
|
||
|
||
xorm supports four drivers now:
|
||
|
||
* Mysql: [github.com/Go-SQL-Driver/MySQL](https://github.com/Go-SQL-Driver/MySQL)
|
||
|
||
* MyMysql: [github.com/ziutek/mymysql/godrv](https://github.com/ziutek/mymysql/godrv)
|
||
|
||
* SQLite: [github.com/mattn/go-sqlite3](https://github.com/mattn/go-sqlite3)
|
||
|
||
* Postgres: [github.com/lib/pq](https://github.com/lib/pq)
|
||
|
||
* MsSql: [github.com/lunny/godbc](https://githubcom/lunny/godbc)
|
||
|
||
NewEngine's parameters are the same as `sql.Open`. So you should read the drivers' document for parameters' usage.
|
||
|
||
After engine created, you can do some settings.
|
||
|
||
1.Logs
|
||
|
||
* `engine.ShowSQL = true`, Show SQL statement on standard output;
|
||
* `engine.ShowDebug = true`, Show debug infomation on standard output;
|
||
* `engine.ShowError = true`, Show error infomation on standard output;
|
||
* `engine.ShowWarn = true`, Show warnning information on standard output;
|
||
|
||
2.If want to record infomation with another method: use `engine.Logger` as `io.Writer`:
|
||
|
||
```Go
|
||
f, err := os.Create("sql.log")
|
||
if err != nil {
|
||
println(err.Error())
|
||
return
|
||
}
|
||
engine.Logger = f
|
||
```
|
||
|
||
3.Engine provide DB connection pool settings.
|
||
|
||
* Use `engine.SetMaxIdleConns()` to set idle connections.
|
||
* Use `engine.SetMaxOpenConns()` to set Max connections. This methods support only Go 1.2+.
|
||
|
||
<a name="20" id="20"></a>
|
||
## 2.Define struct
|
||
|
||
xorm maps a struct to a database table, the rule is below.
|
||
|
||
<a name="21" id="21"></a>
|
||
### 2.1.name mapping rule
|
||
|
||
use xorm.IMapper interface to implement. There are two IMapper implemented: `SnakeMapper` and `SameMapper`. SnakeMapper means struct name is word by word and table name or column name as 下划线. SameMapper means same name between struct and table.
|
||
|
||
SnakeMapper is the default.
|
||
|
||
```Go
|
||
engine.SetMapper(SameMapper{})
|
||
```
|
||
|
||
And you should notice:
|
||
|
||
* If you want to use other mapping rule, implement IMapper
|
||
* Tables's mapping rule could be different from Columns':
|
||
|
||
```Go
|
||
engine.SetTableMapper(SameMapper{})
|
||
engine.SetColumnMapper(SnakeMapper{})
|
||
```
|
||
|
||
<a name="22" id="22"></a>
|
||
### 2.2.Prefix mapping, Suffix Mapping and Cache Mapping
|
||
|
||
* 通过`engine.NewPrefixMapper(SnakeMapper{}, "prefix")`可以在SnakeMapper的基础上在命名中添加统一的前缀，当然也可以把SnakeMapper{}换成SameMapper或者你自定义的Mapper。
|
||
* 通过`engine.NewSufffixMapper(SnakeMapper{}, "suffix")`可以在SnakeMapper的基础上在命名中添加统一的后缀，当然也可以把SnakeMapper{}换成SameMapper或者你自定义的Mapper。
|
||
* 通过`eneing.NewCacheMapper(SnakeMapper{})`可以起到在内存中缓存曾经映射过的命名映射。
|
||
|
||
当然，如果你使用了别的命名规则映射方案，也可以自己实现一个IMapper。
|
||
|
||
<a name="22" id="22"></a>
|
||
### 2.3.Tag mapping
|
||
|
||
如果所有的命名都是按照IMapper的映射来操作的，那当然是最理想的。但是如果碰到某个表名或者某个字段名跟映射规则不匹配时，我们就需要别的机制来改变。
|
||
|
||
通过`engine.Table()`方法可以改变struct对应的数据库表的名称，通过sturct中field对应的Tag中使用`xorm:"'table_name'"`可以使该field对应的Column名称为指定名称。这里使用两个单引号将Column名称括起来是为了防止名称冲突，因为我们在Tag中还可以对这个Column进行更多的定义。如果名称不冲突的情况，单引号也可以不使用。
|
||
|
||
<a name="23" id="23"></a>
|
||
### 2.4.Column defenition
|
||
|
||
我们在field对应的Tag中对Column的一些属性进行定义，定义的方法基本和我们写SQL定义表结构类似，比如：
|
||
|
||
```
|
||
type User struct {
|
||
Id int64
|
||
Name string `xorm:"varchar(25) not null unique 'usr_name'"`
|
||
}
|
||
```
|
||
|
||
For different DBMS, data types对于不同的数据库系统，数据类型其实是有些差异的。因此xorm中对数据类型有自己的定义，基本的原则是尽量兼容各种数据库的字段类型，具体的字段对应关系可以查看[字段类型对应表](https://github.com/go-xorm/xorm/blob/master/docs/COLUMNTYPE.md)。
|
||
|
||
具体的映射规则如下，另Tag中的关键字均不区分大小写，字段名区分大小写：
|
||
|
||
<table>
|
||
<tr>
|
||
<td>name or 'name'</td><td>Column Name, optional</td>
|
||
</tr>
|
||
<tr>
|
||
<td>pk</td><td>If column is Primary Key</td>
|
||
</tr>
|
||
<tr>
|
||
<td>当前支持30多种字段类型，详情参见 [字段类型](https://github.com/go-xorm/xorm/blob/master/docs/COLUMNTYPE.md)</td><td>字段类型</td>
|
||
</tr>
|
||
<tr>
|
||
<td>autoincr</td><td>If autoincrement column</td>
|
||
</tr>
|
||
<tr>
|
||
<td>[not ]null | notnull</td><td>if column could be blank</td>
|
||
</tr>
|
||
<tr>
|
||
<td>unique/unique(uniquename)</td><td>是否是唯一，如不加括号则该字段不允许重复；如加上括号，则括号中为联合唯一索引的名字，此时如果有另外一个或多个字段和本unique的uniquename相同，则这些uniquename相同的字段组成联合唯一索引</td>
|
||
</tr>
|
||
<tr>
|
||
<td>index/index(indexname)</td><td>是否是索引，如不加括号则该字段自身为索引，如加上括号，则括号中为联合索引的名字，此时如果有另外一个或多个字段和本index的indexname相同，则这些indexname相同的字段组成联合索引</td>
|
||
</tr>
|
||
<tr>
|
||
<td>extends</td><td>应用于一个匿名结构体之上，表示此匿名结构体的成员也映射到数据库中</td>
|
||
</tr>
|
||
<tr>
|
||
<td>-</td><td>This field will not be mapping</td>
|
||
</tr>
|
||
<tr>
|
||
<td>-></td><td>这个Field将只写入到数据库而不从数据库读取</td>
|
||
</tr>
|
||
<tr>
|
||
<td><-</td><td>这个Field将只从数据库读取，而不写入到数据库</td>
|
||
</tr>
|
||
<tr>
|
||
<td>created</td><td>This field will be filled in current time on insert</td>
|
||
</tr>
|
||
<tr>
|
||
<td>updated</td><td>This field will be filled in current time on insert or update</td>
|
||
</tr>
|
||
<tr>
|
||
<td>version</td><td>This field will be filled 1 on insert and autoincrement on update</td>
|
||
</tr>
|
||
<tr>
|
||
<td>default 0 | default 'name'</td><td>column default value</td>
|
||
</tr>
|
||
</table>
|
||
|
||
另外有如下几条自动映射的规则：
|
||
|
||
- 1.如果field名称为`Id`而且类型为`int64`的话，会被xorm视为主键，并且拥有自增属性。如果想用`Id`以外的名字做为主键名，可以在对应的Tag上加上`xorm:"pk"`来定义主键。
|
||
|
||
- 2.string类型默认映射为varchar(255)，如果需要不同的定义，可以在tag中自定义
|
||
|
||
- 3.支持`type MyString string`等自定义的field，支持Slice, Map等field成员，这些成员默认存储为Text类型，并且默认将使用Json格式来序列化和反序列化。也支持数据库字段类型为Blob类型，如果是Blob类型，则先使用Json格式序列化再转成[]byte格式。当然[]byte或者[]uint8默认为Blob类型并且都以二进制方式存储。
|
||
|
||
- 4.实现了Conversion接口的类型或者结构体，将根据接口的转换方式在类型和数据库记录之间进行相互转换。
|
||
```Go
|
||
type Conversion interface {
|
||
FromDB([]byte) error
|
||
ToDB() ([]byte, error)
|
||
}
|
||
```
|
||
|
||
<a name="30" id="30"></a>
|
||
## 3.表结构操作
|
||
|
||
xorm提供了一些动态获取和修改表结构的方法。对于一般的应用，很少动态修改表结构，则只需调用Sync()同步下表结构即可。
|
||
|
||
<a name="31" id="31"></a>
|
||
## 3.1 retrieve database meta info
|
||
|
||
* DBMetas()
|
||
xorm支持获取表结构信息，通过调用`engine.DBMetas()`可以获取到所有的表的信息
|
||
|
||
<a name="31" id="31"></a>
|
||
## 3.2.directly table operation
|
||
|
||
* CreateTables()
|
||
创建表使用`engine.CreateTables()`，参数为一个或多个空的对应Struct的指针。同时可用的方法有Charset()和StoreEngine()，如果对应的数据库支持，这两个方法可以在创建表时指定表的字符编码和使用的引擎。当前仅支持Mysql数据库。
|
||
|
||
* IsTableEmpty()
|
||
判断表是否为空，参数和CreateTables相同
|
||
|
||
* IsTableExist()
|
||
判断表是否存在
|
||
|
||
* DropTables()
|
||
删除表使用`engine.DropTables()`，参数为一个或多个空的对应Struct的指针或者表的名字。如果为string传入，则只删除对应的表，如果传入的为Struct，则删除表的同时还会删除对应的索引。
|
||
|
||
<a name="32" id="32"></a>
|
||
## 3.3.create indexes and uniques
|
||
|
||
* CreateIndexes
|
||
根据struct中的tag来创建索引
|
||
|
||
* CreateUniques
|
||
根据struct中的tag来创建唯一索引
|
||
|
||
<a name="34" id="34"></a>
|
||
## 3.4.同步数据库结构
|
||
|
||
同步能够部分智能的根据结构体的变动检测表结构的变动，并自动同步。目前能够实现：
|
||
1) 自动检测和创建表，这个检测是根据表的名字
|
||
2）自动检测和新增表中的字段，这个检测是根据字段名
|
||
3）自动检测和创建索引和唯一索引，这个检测是根据一个或多个字段名，而不根据索引名称
|
||
|
||
调用方法如下：
|
||
```Go
|
||
err := engine.Sync(new(User))
|
||
```
|
||
|
||
<a name="50" id="50"></a>
|
||
## 4.插入数据
|
||
|
||
Inserting records use Insert method.
|
||
|
||
* Insert one record
|
||
```Go
|
||
user := new(User)
|
||
user.Name = "myname"
|
||
affected, err := engine.Insert(user)
|
||
```
|
||
|
||
After inseted, `user.Id` will be filled with primary key column value.
|
||
```Go
|
||
fmt.Println(user.Id)
|
||
```
|
||
|
||
* Insert multiple records by Slice on one table
|
||
```Go
|
||
users := make([]User, 0)
|
||
users[0].Name = "name0"
|
||
...
|
||
affected, err := engine.Insert(&users)
|
||
```
|
||
|
||
* Insert multiple records by Slice of pointer on one table
|
||
```Go
|
||
users := make([]*User, 0)
|
||
users[0] = new(User)
|
||
users[0].Name = "name0"
|
||
...
|
||
affected, err := engine.Insert(&users)
|
||
```
|
||
|
||
* Insert one record on two table.
|
||
```Go
|
||
user := new(User)
|
||
user.Name = "myname"
|
||
question := new(Question)
|
||
question.Content = "whywhywhwy?"
|
||
affected, err := engine.Insert(user, question)
|
||
```
|
||
|
||
* Insert multiple records on multiple tables.
|
||
```Go
|
||
users := make([]User, 0)
|
||
users[0].Name = "name0"
|
||
...
|
||
questions := make([]Question, 0)
|
||
questions[0].Content = "whywhywhwy?"
|
||
affected, err := engine.Insert(&users, &questions)
|
||
```
|
||
|
||
* Insert one or multple records on multiple tables.
|
||
```Go
|
||
user := new(User)
|
||
user.Name = "myname"
|
||
...
|
||
questions := make([]Question, 0)
|
||
questions[0].Content = "whywhywhwy?"
|
||
affected, err := engine.Insert(user, &questions)
|
||
```
|
||
|
||
Notice: If you want to use transaction on inserting, you should use session.Begin() before calling Insert.
|
||
|
||
<a name="60" id="60"></a>
|
||
## 5. Chainable APIs
|
||
|
||
<a name="61" id="61"></a>
|
||
### 5.1. Chainable APIs for Queries, Execusions and Aggregations
|
||
|
||
Queries and Aggregations is basically formed by using `Get`, `Find`, `Count` methods, with conjunction of following chainable APIs to form conditions, grouping and ordering:
|
||
查询和统计主要使用`Get`, `Find`, `Count`三个方法。在进行查询时可以使用多个方法来形成查询条件，条件函数如下：
|
||
|
||
* Id([]interface{})
|
||
Primary Key lookup
|
||
|
||
* Where(string, …interface{})
|
||
As SQL conditional WHERE clause
|
||
|
||
* And(string, …interface{})
|
||
Conditional AND
|
||
|
||
* Or(string, …interface{})
|
||
Conditional OR
|
||
|
||
* Sql(string, …interface{})
|
||
Custom SQL query
|
||
|
||
* Asc(…string)
|
||
Ascending ordering on 1 or more fields
|
||
|
||
* Desc(…string)
|
||
Descending ordering on 1 or more fields
|
||
|
||
* OrderBy(string)
|
||
As SQL ORDER BY
|
||
|
||
* In(string, …interface{})
|
||
As SQL Conditional IN
|
||
|
||
* Cols(…string)
|
||
Explicity specify query or update columns. e.g.,:
|
||
```Go
|
||
engine.Cols("age", "name").Find(&users)
|
||
// SELECT age, name FROM user
|
||
engine.Cols("age", "name").Update(&user)
|
||
// UPDATE user SET age=? AND name=?
|
||
```
|
||
|
||
* Omit(...string)
|
||
Inverse function to Cols, to exclude specify query or update columns. Warning: Don't use with Cols()
|
||
```Go
|
||
engine.Omit("age").Update(&user)
|
||
// UPDATE user SET name = ? AND department = ?
|
||
```
|
||
|
||
* Distinct(…string)
|
||
As SQL DISTINCT
|
||
```Go
|
||
engine.Distinct("age", "department").Find(&users)
|
||
// SELECT DISTINCT age, department FROM user
|
||
```
|
||
Caution: this method will not lookup from caching store
|
||
|
||
|
||
* Table(nameOrStructPtr interface{})
|
||
Specify table name, or if struct pointer is passed into the name is extract from struct type name by IMapper conversion policy
|
||
|
||
* Limit(int, …int)
|
||
As SQL LIMIT with optional second param for OFFSET
|
||
|
||
* Top(int)
|
||
As SQL LIMIT
|
||
|
||
* Join(type, tableName, criteria string)
|
||
As SQL JOIN, support
|
||
type: either of these values [INNER, LEFT OUTER, CROSS] are supported now
|
||
tableName: joining table name
|
||
criteria: join criteria
|
||
|
||
* GroupBy(string)
|
||
As SQL GROUP BY
|
||
|
||
* Having(string)
|
||
As SQL HAVING
|
||
|
||
<a name="62" id="62"></a>
|
||
### 5.2. Override default behavior APIs
|
||
|
||
* NoAutoTime()
|
||
No auto timestamp for Created and Updated fields for INSERT and UPDATE
|
||
|
||
* NoCache()
|
||
Disable cache lookup
|
||
|
||
|
||
* UseBool(...string)
|
||
xorm's default behavior is fields with 0, "", nil, false, will not be used during query or update, use this method to explicit specify bool type fields for query or update
|
||
|
||
|
||
* Cascade(bool)
|
||
Do cascade lookup for associations
|
||
|
||
<a name="50" id="50"></a>
|
||
### 5.3.Get one record
|
||
Fetch a single object by user
|
||
|
||
```Go
|
||
var user = User{Id:27}
|
||
has, err := engine.Get(&user)
|
||
// or has, err := engine.Id(27).Get(&user)
|
||
|
||
var user = User{Name:"xlw"}
|
||
has, err := engine.Get(&user)
|
||
```
|
||
|
||
<a name="60" id="60"></a>
|
||
### 5.4.Find
|
||
Fetch multipe objects into a slice or a map, use Find：
|
||
|
||
```Go
|
||
var everyone []Userinfo
|
||
err := engine.Find(&everyone)
|
||
|
||
users := make(map[int64]Userinfo)
|
||
err := engine.Find(&users)
|
||
```
|
||
|
||
* also you can use Where, Limit
|
||
|
||
```Go
|
||
var allusers []Userinfo
|
||
err := engine.Where("id > ?", "3").Limit(10,20).Find(&allusers) //Get id>3 limit 10 offset 20
|
||
```
|
||
|
||
* or you can use a struct query
|
||
|
||
```Go
|
||
var tenusers []Userinfo
|
||
err := engine.Limit(10).Find(&tenusers, &Userinfo{Name:"xlw"}) //Get All Name="xlw" limit 10 offset 0
|
||
```
|
||
|
||
* or In function
|
||
|
||
```Go
|
||
var tenusers []Userinfo
|
||
err := engine.In("id", 1, 3, 5).Find(&tenusers) //Get All id in (1, 3, 5)
|
||
```
|
||
|
||
* The default will query all columns of a table. Use Cols function if you want to select some columns
|
||
|
||
```Go
|
||
var tenusers []Userinfo
|
||
err := engine.Cols("id", "name").Find(&tenusers) //Find only id and name
|
||
```
|
||
|
||
<a name="70" id="70"></a>
|
||
### 5.5.Iterate records
|
||
Iterate, like find, but handle records one by one
|
||
|
||
```Go
|
||
err := engine.Where("age > ? or name=?)", 30, "xlw").Iterate(new(Userinfo), func(i int, bean interface{})error{
|
||
user := bean.(*Userinfo)
|
||
//do somthing use i and user
|
||
})
|
||
```
|
||
|
||
<a name="66" id="66"></a>
|
||
### 5.6.Count method usage
|
||
|
||
An ORM pointer struct is required for Count method in order to determine which table to retrieve from.
|
||
```Go
|
||
user := new(User)
|
||
total, err := engine.Where("id >?", 1).Count(user)
|
||
```
|
||
|
||
<a name="70" id="70"></a>
|
||
## 6.更新数据
|
||
|
||
更新数据使用`Update`方法，Update方法的第一个参数为需要更新的内容，可以为一个结构体指针或者一个Map[string]interface{}类型。当传入的为结构体指针时，只有非空和0的field才会被作为更新的字段。当传入的为Map类型时，key为数据库Column的名字，value为要更新的内容。
|
||
|
||
```Go
|
||
user := new(User)
|
||
user.Name = "myname"
|
||
affected, err := engine.Id(id).Update(user)
|
||
```
|
||
|
||
这里需要注意，Update会自动从user结构体中提取非0和非nil得值作为需要更新的内容，因此，如果需要更新一个值为0，则此种方法将无法实现，因此有两种选择：
|
||
|
||
1. 通过添加Cols函数指定需要更新结构体中的哪些值，未指定的将不更新，指定了的即使为0也会更新。
|
||
```Go
|
||
affected, err := engine.Id(id).Cols("age").Update(&user)
|
||
```
|
||
|
||
2. 通过传入map[string]interface{}来进行更新，但这时需要额外指定更新到哪个表，因为通过map是无法自动检测更新哪个表的。
|
||
```Go
|
||
affected, err := engine.Table(new(User)).Id(id).Update(map[string]interface{}{"age":0})
|
||
```
|
||
|
||
|
||
### 6.1.乐观锁
|
||
|
||
要使用乐观锁，需要使用version标记
|
||
type User struct {
|
||
Id int64
|
||
Name string
|
||
Version int `xorm:"version"`
|
||
}
|
||
|
||
在Insert时，version标记的字段将会被设置为1，在Update时，Update的内容必须包含version原来的值。
|
||
|
||
```Go
|
||
var user User
|
||
engine.Id(1).Get(&user)
|
||
// SELECT * FROM user WHERE id = ?
|
||
engine.Id(1).Update(&user)
|
||
// UPDATE user SET ..., version = version + 1 WHERE id = ? AND version = ?
|
||
```
|
||
|
||
|
||
<a name="80" id="80"></a>
|
||
## 7.Delete one or more records
|
||
Delete one or more records
|
||
|
||
* delete by id
|
||
|
||
```Go
|
||
err := engine.Id(1).Delete(&User{})
|
||
```
|
||
|
||
* delete by other conditions
|
||
|
||
```Go
|
||
err := engine.Delete(&User{Name:"xlw"})
|
||
```
|
||
|
||
<a name="90" id="90"></a>
|
||
## 8.Execute SQL query
|
||
|
||
Of course, SQL execution is also provided.
|
||
|
||
If select then use Query
|
||
|
||
```Go
|
||
sql := "select * from userinfo"
|
||
results, err := engine.Query(sql)
|
||
```
|
||
|
||
<a name="100" id="100"></a>
|
||
## 9.Execute SQL command
|
||
If insert, update or delete then use Exec
|
||
|
||
```Go
|
||
sql = "update userinfo set username=? where id=?"
|
||
res, err := engine.Exec(sql, "xiaolun", 1)
|
||
```
|
||
|
||
<a name="110" id="110"></a>
|
||
## 10.Transaction
|
||
|
||
```Go
|
||
session := engine.NewSession()
|
||
defer session.Close()
|
||
|
||
// add Begin() before any action
|
||
err := session.Begin()
|
||
user1 := Userinfo{Username: "xiaoxiao", Departname: "dev", Alias: "lunny", Created: time.Now()}
|
||
_, err = session.Insert(&user1)
|
||
if err != nil {
|
||
session.Rollback()
|
||
return
|
||
}
|
||
user2 := Userinfo{Username: "yyy"}
|
||
_, err = session.Where("id = ?", 2).Update(&user2)
|
||
if err != nil {
|
||
session.Rollback()
|
||
return
|
||
}
|
||
|
||
_, err = session.Exec("delete from userinfo where username = ?", user2.Username)
|
||
if err != nil {
|
||
session.Rollback()
|
||
return
|
||
}
|
||
|
||
// add Commit() after all actions
|
||
err = session.Commit()
|
||
if err != nil {
|
||
return
|
||
}
|
||
```
|
||
|
||
<a name="120" id="120"></a>
|
||
## 11.Built-in LRU memory cache provider
|
||
|
||
1. Global Cache
|
||
Xorm implements cache support. Defaultly, it's disabled. If enable it, use below code.
|
||
|
||
```Go
|
||
cacher := xorm.NewLRUCacher(xorm.NewMemoryStore(), 1000)
|
||
engine.SetDefaultCacher(cacher)
|
||
```
|
||
|
||
If disable some tables' cache, then:
|
||
|
||
```Go
|
||
engine.MapCacher(&user, nil)
|
||
```
|
||
|
||
2. Table's Cache
|
||
If only some tables need cache, then:
|
||
|
||
```Go
|
||
cacher := xorm.NewLRUCacher(xorm.NewMemoryStore(), 1000)
|
||
engine.MapCacher(&user, cacher)
|
||
```
|
||
|
||
Caution:
|
||
|
||
1. When use Cols methods on cache enabled, the system still return all the columns.
|
||
|
||
2. When using Exec method, you should clear cache：
|
||
|
||
```Go
|
||
engine.Exec("update user set name = ? where id = ?", "xlw", 1)
|
||
engine.ClearCache(new(User))
|
||
```
|
||
|
||
Cache implement theory below:
|
||
|
||
|
||
|
||
<a name="130" id="130"></a>
|
||
## 12.xorm tool
|
||
xorm commandl line tool
|
||
|
||
### 12.1.Reverse command
|
||
Please visit [xorm tool](https://github.com/go-xorm/cmd)
|
||
|
||
<a name="140" id="140"></a>
|
||
## 13.Examples
|
||
|
||
Please visit [https://github.com/go-xorm/xorm/tree/master/examples](https://github.com/go-xorm/xorm/tree/master/examples)
|
||
|
||
<a name="150" id="150"></a>
|
||
## 14.Cases
|
||
|
||
* [Gowalker](http://gowalker.org)，source [github.com/Unknwon/gowalker](http://github.com/Unknwon/gowalker)
|
||
|
||
* [GoDaily](http://godaily.org)，source [github.com/govc/godaily](http://github.com/govc/godaily)
|
||
|
||
* [Sudochina](http://sudochina.com) source [github.com/insionng/toropress](http://github.com/insionng/toropress)
|
||
|
||
* [VeryHour](http://veryhour.com)
|
||
|
||
<a name="160"></a>
|
||
## 15.FAQ
|
||
|
||
1.How the xorm tag use both with json?
|
||
|
||
Use space.
|
||
|
||
```Go
|
||
type User struct {
|
||
Name string `json:"name" xorm:"name"`
|
||
}
|
||
```
|