357 lines
8.2 KiB
Markdown
357 lines
8.2 KiB
Markdown
# Quick Start
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1.Create a database engine just like sql.Open, commonly you just need create once. Please notice, Create function will be deprecated, use NewEngine instead.
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```Go
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import (
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_ "github.com/Go-SQL-Driver/MySQL"
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"github.com/lunny/xorm"
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)
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engine, err := xorm.NewEngine("mysql", "root:123@/test?charset=utf8")
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defer engine.Close()
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```
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or
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```Go
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import (
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_ "github.com/mattn/go-sqlite3"
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"github.com/lunny/xorm"
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)
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engine, err = xorm.NewEngine("sqlite3", "./test.db")
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defer engine.Close()
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```
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1.1.If you want to show all generated SQL
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```Go
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engine.ShowSQL = true
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```
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1.2 If you want to use your own connection pool
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```Go
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err = engine.SetPool(NewSimpleConnectPool())
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```
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1.3 If you want to auto sync database schema
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```Go
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err = engine.Sync(new(User), new(Category))
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```
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1.4 If you want to enable cache system
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```Go
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cacher := xorm.NewLRUCacher(xorm.NewMemoryStore(), 1000)
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Engine.SetDefaultCacher(cacher)
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```
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2.Define a struct
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```Go
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type User struct {
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Id int
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Name string
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Age int `xorm:"-"`
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}
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```
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2.1.More mapping rules, please see [Mapping Rules](#mapping)
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3.When you set up your program, you can use CreateTables to create database tables.
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```Go
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err := engine.CreateTables(&User{})
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// or err := engine.Map(&User{}, &Article{})
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// err = engine.CreateAll()
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```
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4.then, insert a struct to table, if success, User.Id will be set to id
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```Go
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id, err := engine.Insert(&User{Name:"lunny"})
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```
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or if you want to update records
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```Go
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user := User{Name:"xlw"}
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rows, err := engine.Update(&user, &User{Id:1})
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// or rows, err := engine.Where("id = ?", 1).Update(&user)
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// or rows, err := engine.Id(1).Update(&user)
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```
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5.Fetch a single object by user
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```Go
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var user = User{Id:27}
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has, err := engine.Get(&user)
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// or has, err := engine.Id(27).Get(&user)
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var user = User{Name:"xlw"}
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has, err := engine.Get(&user)
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```
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6.Fetch multipe objects into a slice or a map, use Find：
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```Go
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var everyone []Userinfo
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err := engine.Find(&everyone)
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users := make(map[int64]Userinfo)
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err := engine.Find(&users)
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```
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6.1 also you can use Where, Limit
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```Go
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var allusers []Userinfo
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err := engine.Where("id > ?", "3").Limit(10,20).Find(&allusers) //Get id>3 limit 10 offset 20
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```
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6.2 or you can use a struct query
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```Go
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var tenusers []Userinfo
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err := engine.Limit(10).Find(&tenusers, &Userinfo{Name:"xlw"}) //Get All Name="xlw" limit 10 offset 0
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```
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6.3 or In function
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```Go
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var tenusers []Userinfo
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err := engine.In("id", 1, 3, 5).Find(&tenusers) //Get All id in (1, 3, 5)
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```
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6.4 The default will query all columns of a table. Use Cols function if you want to select some columns
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```Go
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var tenusers []Userinfo
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err := engine.Cols("id", "name").Find(&tenusers) //Find only id and name
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```
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7.Delete
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7.1 deleted by id
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```Go
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err := engine.Id(1).Delete(&User{})
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```
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7.2 deleted by other conditions
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```Go
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err := engine.Delete(&User{Name:"xlw"})
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```
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8.Count
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```Go
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total, err := engine.Where("id > ?", 5).Count(&User{Name:"xlw"})
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```
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9.Cache
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```Go
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cacher := xorm.NewLRUCacher(xorm.NewMemoryStore(), 1000)
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engine.SetDefaultCacher(cacher)
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```
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## Execute SQL
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Of course, SQL execution is also provided.
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1.if select then use Query
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```Go
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sql := "select * from userinfo"
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results, err := engine.Query(sql)
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```
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2.if insert, update or delete then use Exec
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```Go
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sql = "update userinfo set username=? where id=?"
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res, err := engine.Exec(sql, "xiaolun", 1)
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```
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## Advanced Usage
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For deep usage, you should create a session.
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```Go
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session := engine.NewSession()
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defer session.Close()
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```
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1.Fetch a single object by where, these methods are same to engine.
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```Go
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var user Userinfo
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session.Where("id=?", 27).Get(&user)
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var userJohn Userinfo
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session.Where("name = ?", "john").Get(&userJohn) // more complex query
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var userOldJohn Userinfo
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session.Where("name = ? and age > ?", "john", 88).Get(&userOldJohn) // even more complex
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```
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2.Fetch multiple objects
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```Go
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var allusers []Userinfo
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err := session.Where("id > ?", "3").Limit(10,20).Find(&allusers) //Get id>3 limit 10 offset 20
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var tenusers []Userinfo
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err := session.Limit(10).Find(&tenusers, &Userinfo{Name:"xlw"}) //Get All Name="xlw" limit 10 if omit offset the default is 0
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var everyone []Userinfo
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err := session.Find(&everyone)
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```
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3.Transaction
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```Go
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// add Begin() before any action
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err := session.Begin()
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user1 := Userinfo{Username: "xiaoxiao", Departname: "dev", Alias: "lunny", Created: time.Now()}
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_, err = session.Insert(&user1)
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if err != nil {
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session.Rollback()
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return
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}
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user2 := Userinfo{Username: "yyy"}
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_, err = session.Where("id = ?", 2).Update(&user2)
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if err != nil {
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session.Rollback()
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return
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}
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_, err = session.Delete(&user2)
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if err != nil {
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session.Rollback()
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return
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}
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// add Commit() after all actions
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err = session.Commit()
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if err != nil {
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return
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}
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```
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4.Mixed Transaction
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```Go
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// add Begin() before any action
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err := session.Begin()
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user1 := Userinfo{Username: "xiaoxiao", Departname: "dev", Alias: "lunny", Created: time.Now()}
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_, err = session.Insert(&user1)
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if err != nil {
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session.Rollback()
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return
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}
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user2 := Userinfo{Username: "yyy"}
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_, err = session.Where("id = ?", 2).Update(&user2)
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if err != nil {
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session.Rollback()
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return
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}
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_, err = session.Exec("delete from userinfo where username = ?", user2.Username)
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if err != nil {
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session.Rollback()
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return
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}
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// add Commit() after all actions
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err = session.Commit()
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if err != nil {
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return
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}
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```
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5.Derive mapping
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Please see derive.go in examples folder.
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## Mapping Rules
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<a name="mapping" id="mapping"></a>
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1.Struct and struct's fields name should be Pascal style, and the table and column's name default is SQL style.
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For example:
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The struct's Name 'UserInfo' will turn into the table name 'user_info', the same as the keyname. If the keyname is 'UserName' will turn into the select colum 'user_name'
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2.If You want change the mapping rules, you have two methods. One is to implement your own Map struct interface according IMapper, you can find the interface in mapper.go and set it to engine.Mapper
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Another is use field tag, field tag support the below keywords which split with space:
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<table>
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<tr>
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<td>name</td><td>column name, if no this name, the name is auto generated according field name and mapper rule.</td>
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</tr>
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<tr>
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<td>pk</td><td>the field is a primary key</td>
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</tr>
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<tr>
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<td>more than 30 column type supported, please see [Column Type](https://github.com/lunny/xorm/blob/master/docs/COLUMNTYPE.md)</td><td>column type</td>
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</tr>
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<tr>
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<td>autoincr</td><td>auto incrment</td>
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</tr>
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<tr>
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<td>[not ]null</td><td>if column can be null value</td>
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</tr>
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<tr>
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<td>unique or unique(uniquename)</td><td>unique or union unique as uniquename</td>
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</tr>
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<tr>
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<td>index or index(indexname)</td><td>index or union index as indexname</td>
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</tr>
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<tr>
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<td>extends</td><td>used in anonymous struct means mapping this struct's fields to table</td>
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</tr>
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<tr>
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<td>-</td><td>this field is not map as a table column</td>
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</tr>
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<tr>
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<td>-></td><td>this field only write to db and not read from db</td>
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</tr>
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<tr>
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<td><-</td><td>this field only read from db and not write to db</td>
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</tr>
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<tr>
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<td>created</td><td>this field will auto fill current time when insert</td>
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</tr>
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<tr>
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<td>updated</td><td>this field will auto fill current time when update</td>
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</tr>
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<tr>
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<td>default 0 or default 'abc'</td><td>default value, use single quote for string</td>
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</tr>
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</table>
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For Example
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```Go
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type Userinfo struct {
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Uid int `xorm:"id pk not null autoincr"`
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Username string `xorm:"unique"`
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Departname string
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Alias string `xorm:"-"`
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Created time.Time
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}
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```
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3.For customize table name, use Table() function, for example:
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```Go
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// batch create tables
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for i := 0; i < 10; i++ {
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engine.Table(fmt.Sprintf("user_%v", i)).CreateTable(&Userinfo{})
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}
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// insert into table according id
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user := Userinfo{Uid: 25, Username:"sslfs"}
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engine.Table(fmt.Sprintf("user_%v", user.Uid % 10)).Insert(&user)
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``` |