Go语言ORM库xrom

xorm是个简单强大的Go语言ORM库使数据库操作非常简便
特性
支持Struct和数据库表之间的灵活映射并支持自动同步
事务支持
同时支持原始SQL语句和ORM操作的混合执行
使用连写来简化调用
支持使用Id, In, Where, Limit, Join, Having, Table, Sql, Cols等函数和结构体等方式作为条件
支持级联加载Struct
Schema支持（仅Postgres）
支持缓存
支持根据数据库自动生成xorm的结构体
支持记录版本（即乐观锁）
内置SQL Builder支持
上下文缓存支持

驱动支持

目前支持的Go数据库驱动和对应的数据库如下
Mysql: github.com/go-sql-driver/mysql
MyMysql: github.com/ziutek/mymysql/godrv
Postgres: github.com/lib/pq
Tidb: github.com/pingcap/tidb
SQLite: github.com/mattn/go-sqlite3
MsSql: github.com/denisenkom/go-mssqldb
MsSql: github.com/lunny/godbc
Oracle: github.com/mattn/go-oci8 (试验性支持)
安装 go get github.com/go-xorm/xorm

操作指南

第一步创建引擎 driverName dataSourceName 和 database/sql 接口相同
engine, err := xorm.NewEngine(driverName, dataSourceName)
定义一个和表同步的结构体并且自动同步结构体到数据库
type User struct {
Id int64
Name string
Salt string
Age int
Passwd string `xorm:"varchar(200)"`
Created time.Time `xorm:"created"`
Updated time.Time `xorm:"updated"`
}
err := engine.Sync2(new(User))
创建Engine组
dataSourceNameSlice := []string{masterDataSourceName, slave1DataSourceName, slave2DataSourceName}
engineGroup, err := xorm.NewEngineGroup(driverName, dataSourceNameSlice)
masterEngine, err := xorm.NewEngine(driverName, masterDataSourceName)
slave1Engine, err := xorm.NewEngine(driverName, slave1DataSourceName)
slave2Engine, err := xorm.NewEngine(driverName, slave2DataSourceName)
engineGroup, err := xorm.NewEngineGroup(masterEngine, []*Engine{slave1Engine, slave2Engine})
所有使用 engine 都可以简单的用 engineGroup 来替换
Query 最原始的也支持SQL语句查询返回的结果类型为 []map[string][]byte
QueryString 返回 []map[string]string
QueryInterface 返回 []map[string]interface{}
results, err := engine.Query("select * from user")
results, err := engine.Where("a = 1").Query()
results, err := engine.QueryString("select * from user")
results, err := engine.Where("a = 1").QueryString()
results, err := engine.QueryInterface("select * from user")
results, err := engine.Where("a = 1").QueryInterface()
Exec 执行一个SQL语句
affected, err := engine.Exec("update user set age = ? where name = ?", age, name)
Insert 插入一条或者多条记录
affected, err := engine.Insert(&user)
// INSERT INTO struct () values ()
affected, err := engine.Insert(&user1, &user2)
// INSERT INTO struct1 () values ()
// INSERT INTO struct2 () values ()
affected, err := engine.Insert(&users)
// INSERT INTO struct () values (),(),()
affected, err := engine.Insert(&user1, &users)
// INSERT INTO struct1 () values ()
// INSERT INTO struct2 () values (),(),()

Get 查询单条记录

has, err := engine.Get(&user)// SELECT * FROM user LIMIT 1
has, err := engine.Where("name = ?", name).Desc("id").Get(&user)
// SELECT * FROM user WHERE name = ? ORDER BY id DESC LIMIT 1
var name string
has, err := engine.Table(&user).Where("id = ?", id).Cols("name").Get(&name)
// SELECT name FROM user WHERE id = ?

var id int64
has, err := engine.Table(&user).Where("name = ?", name).Cols("id").Get(&id)
has, err := engine.SQL("select id from user").Get(&id)// SELECT id FROM user WHERE name = ?
var valuesMap = make(map[string]string)
has, err := engine.Table(&user).Where("id = ?", id).Get(&valuesMap)
// SELECT * FROM user WHERE id = ?

var valuesSlice = make([]interface{}, len(cols))
has, err := engine.Table(&user).Where("id = ?", id).Cols(cols...).Get(&valuesSlice)
// SELECT col1, col2, col3 FROM user WHERE id = ?

Exist 检测记录是否存在

has, err := engine.Exist(new(RecordExist))// SELECT * FROM record_exist LIMIT 1
has, err = engine.Exist(&RecordExist{Name: "test1",})// SELECT * FROM record_exist WHERE name = ? LIMIT 1
has, err = engine.Where("name = ?", "test1").Exist(&RecordExist{})// SELECT * FROM record_exist WHERE name = ? LIMIT 1
has, err = engine.SQL("select * from record_exist where name = ?", "test1").Exist()// select * from record_exist where name = ?
has, err = engine.Table("record_exist").Exist()// SELECT * FROM record_exist LIMIT 1
has, err = engine.Table("record_exist").Where("name = ?", "test1").Exist()// SELECT * FROM record_exist WHERE name = ? LIMIT 1

Find 查询多条记录

当然可以使用Join和extends来组合使用
var users []User
err := engine.Where("name = ?", name).And("age > 10").Limit(10, 0).Find(&users)
// SELECT * FROM user WHERE name = ? AND age > 10 limit 10 offset 0
type Detail struct {
Id int64
UserId int64 `xorm:"index"`
}
type UserDetail struct {
User `xorm:"extends"`
Detail `xorm:"extends"`
}
var users []UserDetail
err := engine.Table("user").Select("user.*, detail.*")
Join("INNER", "detail", "detail.user_id = user.id").
Where("user.name = ?", name).Limit(10, 0).Find(&users)
// SELECT user.*, detail.* FROM user INNER JOIN detail WHERE user.name = ? limit 10 offset 0

Iterate 和 Rows 条件遍历数据库

可以有两种方式: Iterate and Rows
err := engine.Iterate(&User{Name:name}, func(idx int, bean interface{}) error {
user := bean.(*User)
return nil
})// SELECT * FROM user
err := engine.BufferSize(100).Iterate(&User{Name:name}, func(idx int, bean interface{}) error {
user := bean.(*User)
return nil
})
// SELECT * FROM user Limit 0, 100
// SELECT * FROM user Limit 101, 100

rows, err := engine.Rows(&User{Name:name})// SELECT * FROM user
defer rows.Close()
bean := new(Struct)
for rows.Next() {
err = rows.Scan(bean)
}

Update 更新数据

除非使用Cols,AllCols函数指明默认只更新非空和非0的字段
affected, err := engine.ID(1).Update(&user)// UPDATE user SET ... Where id = ?
affected, err := engine.Update(&user, &User{Name:name})// UPDATE user SET ... Where name = ?
var ids = []int64{1, 2, 3}
affected, err := engine.In(ids).Update(&user)// UPDATE user SET ... Where id IN (?, ?, ?)
// force update indicated columns by Cols
affected, err := engine.ID(1).Cols("age").Update(&User{Name:name, Age: 12})
// UPDATE user SET age = ?, updated=? Where id = ?
// force NOT update indicated columns by Omit
affected, err := engine.ID(1).Omit("name").Update(&User{Name:name, Age: 12})
// UPDATE user SET age = ?, updated=? Where id = ?
affected, err := engine.ID(1).AllCols().Update(&user)
// UPDATE user SET name=?,age=?,salt=?,passwd=?,updated=? Where id = ?
Delete 删除记录需要注意删除必须至少有一个条件否则会报错。要清空数据库可以用EmptyTable
affected, err := engine.Where(...).Delete(&user)// DELETE FROM user Where ...
affected, err := engine.ID(2).Delete(&user)// DELETE FROM user Where id = ?

Count 获取记录条数

counts, err := engine.Count(&user)// SELECT count(*) AS total FROM user

Sum 求和函数

agesFloat64, err := engine.Sum(&user, "age")// SELECT sum(age) AS total FROM user
agesInt64, err := engine.SumInt(&user, "age")// SELECT sum(age) AS total FROM user
sumFloat64Slice, err := engine.Sums(&user, "age", "score")// SELECT sum(age), sum(score) FROM user
sumInt64Slice, err := engine.SumsInt(&user, "age", "score")// SELECT sum(age), sum(score) FROM user

条件编辑器

err := engine.Where(builder.NotIn("a", 1, 2).And(builder.In("b", "c", "d", "e"))).Find(&users)
// SELECT id, name ... FROM user WHERE a NOT IN (?, ?) AND b IN (?, ?, ?)
在一个Go程中多次操作数据库但没有事务
session := engine.NewSession()
defer session.Close()
user1 := Userinfo{Username: "xiaoxiao", Departname: "dev", Alias: "lunny", Created: time.Now()}
if _, err := session.Insert(&user1); err != nil {
return err
}
user2 := Userinfo{Username: "yyy"}
if _, err := session.Where("id = ?", 2).Update(&user2); err != nil {
return err
}
if _, err := session.Exec("delete from userinfo where username = ?", user2.Username); err != nil {
return err
}
return nil

在一个Go程中有事务

session := engine.NewSession()
defer session.Close()
// add Begin() before any action
if err := session.Begin(); err != nil {
// if returned then will rollback automatically
return err
}
user1 := Userinfo{Username: "xiaoxiao", Departname: "dev", Alias: "lunny", Created: time.Now()}
if _, err := session.Insert(&user1); err != nil {
return err
}
user2 := Userinfo{Username: "yyy"}
if _, err := session.Where("id = ?", 2).Update(&user2); err != nil {
return err
}
if _, err := session.Exec("delete from userinfo where username = ?", user2.Username); err != nil {
return err
}// add Commit() after all actions
return session.Commit()

事务的简写方法

res, err := engine.Transaction(func(session *xorm.Session) (interface{}, error) {
user1 := Userinfo{Username: "xiaoxiao", Departname: "dev", Alias: "lunny", Created: time.Now()}
if _, err := session.Insert(&user1); err != nil {
       return nil, err
}
user2 := Userinfo{Username: "yyy"}
if _, err := session.Where("id = ?", 2).Update(&user2); err != nil {
       return nil, err
}
if _, err := session.Exec("delete from userinfo where username = ?", user2.Username); err != nil {
       return nil, err
}
return nil, nil
})上下文缓存如果启用那么针对单个对象的查询将会被缓存到系统中可以被下一个查询使用
sess := engine.NewSession()
defer sess.Close()
var context = xorm.NewMemoryContextCache()
var c2 ContextGetStruct
has, err := sess.ID(1).ContextCache(context).Get(&c2)
assert.NoError(t, err)
assert.True(t, has)
assert.EqualValues(t, 1, c2.Id)
assert.EqualValues(t, "1", c2.Name)
sql, args := sess.LastSQL()
assert.True(t, len(sql) > 0)
assert.True(t, len(args) > 0)
var c3 ContextGetStruct
has, err = sess.ID(1).ContextCache(context).Get(&c3)
assert.NoError(t, err)
assert.True(t, has)
assert.EqualValues(t, 1, c3.Id)
assert.EqualValues(t, "1", c3.Name)
sql, args = sess.LastSQL()
assert.True(t, len(sql) == 0)
assert.True(t, len(args) == 0)