22.常用orm框架
Go常用orm框架
1.xorm
xorm是一个简答而强大的Go语言ORM库，通过它可以使数据库操作非常方便。
官网：https://xorm.io
中文文档：https://gitea.com/xorm/xorm/src/branch/master/README_CN.md
1.1.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ID，In，Where,Limit,join, Having,Table,SQL,Cols等函数和结构体等方式作为条件
-
....
1.2.安装
go get xorm.io/xorm
demo01.go
package main
import (
"fmt"
)
func main() {
//数据库连接基本信息
var (
userName string = "root"
password string = "123456"
idAddress string = "127.0.0.1"
port int = 3306
dbName string = "go_test"
charset string = "utf8mb4"
)
//构建数据库连接信息
fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?charset=%s", userName, password, idAddress, port, dbName, charset)
}
1.3.同步结构体到数据库
-
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.Sync(new(User))
完整代码
package main
import (
"fmt"
_ "github.com/go-sql-driver/mysql"
"time"
"xorm.io/xorm"
)
func main() {
//数据库连接基本信息
var (
userName string = "root"
password string = "123456"
idAddress string = "127.0.0.1"
port int = 3306
dbName string = "go_test"
charset string = "utf8mb4"
)
//构建数据库连接信息
dataSourceName := fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?charset=%s", userName, password, idAddress, port, dbName, charset)
//创建引擎
engine, err := xorm.NewEngine("mysql", dataSourceName)
if err != nil {
fmt.Println("连接失败")
}
type User struct {
Id int64
Name string
Salt string
Age int
Avatar string
Passwd string `xorm:"varchar(200)"`
Created time.Time `xorm:"created"`
Updated time.Time `xorm:"updated"`
}
err = engine.Sync(new(User))
if err != nil {
fmt.Println("表结构同步失败")
}
}
1.4.插入数据
官方实例
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 (),(),()
affected, err := engine.Table("user").Insert(map[string]interface{}{
"name": "lunny",
"age": 18,
})
// INSERT INTO user (name, age) values (?,?)
affected, err := engine.Table("user").Insert([]map[string]interface{}{
{
"name": "lunny",
"age": 18,
},
{
"name": "lunny2",
"age": 19,
},
})
// INSERT INTO user (name, age) values (?,?),(?,?)
笔记代码
package main
import (
"fmt"
_ "github.com/go-sql-driver/mysql"
"time"
"xorm.io/xorm"
)
func main() {
//数据库连接基本信息
var (
userName string = "root"
password string = "123456"
idAddress string = "127.0.0.1"
port int = 3306
dbName string = "go_test"
charset string = "utf8mb4"
)
//构建数据库连接信息
dataSourceName := fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?charset=%s", userName, password, idAddress, port, dbName, charset)
//创建引擎
engine, err := xorm.NewEngine("mysql", dataSourceName)
if err != nil {
fmt.Println("连接失败")
}
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"`
}
//engine.Insert() 插入 对象，返回值：受影响的行数
user := User{Id: 1000, Name: "zjzaki", Age: 18, Passwd: "123456"}
n, _ := engine.Insert(&user)
if n >= 1 {
fmt.Println("数据插入成功")
}
fmt.Println(n)
user1 := User{Id: 10001, Name: "zjzaki", Age: 18, Passwd: "123456"}
user2 := User{Id: 10002, Name: "zjzaki", Age: 18, Passwd: "123456"}
n, _ = engine.Insert(&user1, &user2)
if n >= 1 {
fmt.Println("数据插入成功")
}
fmt.Println(n)
var users []User
users = append(users, User{Id: 10003, Name: "zjzaki", Age: 18, Passwd: "123456"})
users = append(users, User{Id: 10004, Name: "zjzaki", Age: 18, Passwd: "123456"})
n, _ = engine.Insert(users)
}
1.5.更新与删除
Update更新数据，默认只更新非空和非0的字段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Exec执行一个SQL语句
官方示例
1.5.1.更新数据
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 = ?
1.5.2.删除数据
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 = ?
affected, err := engine.Table("user").Where(...).Delete()
// DELETE FROM user WHERE ...
1.6.查询数据
1.6.1.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 id int64
var name string
has, err := engine.Table(&user).Cols("id", "name").Get(&id, &name)
// SELECT id, name FROM user LIMIT 1
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 = ?
1.6.2.Exist 检测记录是否存在
has, err := testEngine.Exist(new(RecordExist))
// SELECT * FROM record_exist LIMIT 1
has, err = testEngine.Exist(&RecordExist{
Name: "test1",
})
// SELECT * FROM record_exist WHERE name = ? LIMIT 1
has, err = testEngine.Where("name = ?", "test1").Exist(&RecordExist{})
// SELECT * FROM record_exist WHERE name = ? LIMIT 1
has, err = testEngine.SQL("select * from record_exist where name = ?", "test1").Exist()
// select * from record_exist where name = ?
has, err = testEngine.Table("record_exist").Exist()
// SELECT * FROM record_exist LIMIT 1
has, err = testEngine.Table("record_exist").Where("name = ?", "test1").Exist()
// SELECT * FROM record_exist WHERE name = ? LIMIT 1
1.6.3.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
1.6.4.Iterate 和 Rows 根据条件遍历数据库，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 的用法类似 sql.Rows。
rows, err := engine.Rows(&User{Name:name})
// SELECT * FROM user
defer rows.Close()
bean := new(Struct)
for rows.Next() {
err = rows.Scan(bean)
}
或者
rows, err := engine.Cols("name", "age").Rows(&User{Name:name})
// SELECT * FROM user
defer rows.Close()
for rows.Next() {
var name string
var age int
err = rows.Scan(&name, &age)
}
1.6.5.Count 获取记录条数
counts, err := engine.Count(&user)
// SELECT count(*) AS total FROM user
1.6.6.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
1.6.7.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 (?, ?, ?)
1.7.事务
1.7.1.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
1.7.2.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()
1.7.3.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
})
1.7.4.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)
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