Beego Models 之 一ORM 使用方法

go get github.com/astaxie/beego/orm

package main

import (
    "github.com/astaxie/beego/orm" //导入包
)

//定义 struct和数据表进行映射的
type User struct {
    Id          int
    Name        string
    Profile     *Profile   `orm:"rel(one)"` // OneToOne relation
    Post        []*Post `orm:"reverse(many)"` // 设置一对多的反向关系
}

type Profile struct {
    Id          int
    Age         int16
    User        *User   `orm:"reverse(one)"` // 设置一对一反向关系(可选)
}

type Post struct {
    Id    int
    Title string
    User  *User  `orm:"rel(fk)"`    //设置一对多关系
    Tags  []*Tag `orm:"rel(m2m)"`
}

type Tag struct {
    Id    int
    Name  string
    Posts []*Post `orm:"reverse(many)"`
}

func init() {
    // 需要在init中注册定义的model
    orm.RegisterModel(new(User), new(Post), new(Profile), new(Tag))
}

package main

import (
    "fmt"
    "github.com/astaxie/beego/orm"
    _ "github.com/go-sql-driver/mysql" // 只是调用init方法
)

func init() {
    orm.RegisterDriver("mysql", orm.DRMySQL)

    orm.RegisterDataBase("default", "mysql", "root:root@/orm_test?charset=utf8")
}

func main() {
    o := orm.NewOrm()
    o.Using("default") // 默认使用 default，你可以指定为其他数据库

    profile := new(Profile)
    profile.Age = 30

    user := new(User)
    user.Profile = profile
    user.Name = "slene"

    fmt.Println(o.Insert(profile))
    fmt.Println(o.Insert(user))
}

import (
    _ "github.com/go-sql-driver/mysql"
    _ "github.com/lib/pq"
    _ "github.com/mattn/go-sqlite3"
)

// For version 1.6
orm.DRMySQL
orm.DRSqlite
orm.DRPostgres

// < 1.6
orm.DR_MySQL
orm.DR_Sqlite
orm.DR_Postgres

// 参数1   driverName
// 参数2   数据库类型
// 这个用来设置 driverName 对应的数据库类型
// mysql / sqlite3 / postgres 这三种是默认已经注册过的，所以可以无需设置
orm.RegisterDriver("mysql", orm.DRMySQL)

// RegisterDataBase Setting the database connect params. Use the database driver self dataSource args.
func RegisterDataBase(aliasName, driverName, dataSource string, params ...int) error {
    var (
        err error
        db  *sql.DB
        al  *alias
    )

    db, err = sql.Open(driverName, dataSource)
    if err != nil {
        err = fmt.Errorf("register db `%s`, %s", aliasName, err.Error())
        goto end
    }

    al, err = addAliasWthDB(aliasName, driverName, db)
    if err != nil {
        goto end
    }

    al.DataSource = dataSource

    detectTZ(al)

    for i, v := range params {
        switch i {
        case 0:
            SetMaxIdleConns(al.Name, v)
        case 1:
            SetMaxOpenConns(al.Name, v)
        }
    }

end:
    if err != nil {
        if db != nil {
            db.Close()
        }
        DebugLog.Println(err.Error())
    }

    return err
}

// 参数1        数据库的别名，用来在 ORM 中切换数据库使用
// 参数2        driverName
// 参数3        对应的链接字符串
orm.RegisterDataBase("default", "mysql", "root:root@/orm_test?charset=utf8")

// 参数4(可选)  设置最大空闲连接
// 参数5(可选)  设置最大数据库连接 (go >= 1.2)
maxIdle := 30
maxConn := 30
orm.RegisterDataBase("default", "mysql", "root:root@/orm_test?charset=utf8", maxIdle, maxConn)

orm.SetMaxIdleConns("default", 30)

orm.SetMaxOpenConns("default", 30)

// 设置为 UTC 时间
orm.DefaultTimeLoc = time.UTC

package main

import "github.com/astaxie/beego/orm"

type User struct {
    Id   int
    Name string
}

func init(){
    orm.RegisterModel(new(User))
}

orm.RegisterModel(new(User), new(Profile), new(Post))

orm.RegisterModelWithPrefix("prefix_", new(User))

var driverName, aliasName string
// driverName 是驱动的名称
// aliasName 是当前 db 的自定义别名
var db *sql.DB
...
o := orm.NewOrmWithDB(driverName, aliasName, db)

db, err := orm.GetDB()
if err != nil {
    fmt.Println("get default DataBase")
}

db, err := orm.GetDB("alias")
if err != nil {
    fmt.Println("get alias DataBase")
}

orm.ResetModelCache()

var o Ormer
o = orm.NewOrm() // 创建一个 Ormer
// NewOrm 的同时会执行 orm.BootStrap (整个 app 只执行一次)，用以验证模型之间的定义并缓存。

// Ormer define the orm interface
type Ormer interface {
    // read data to model
    // for example:
    //  this will find User by Id field
    //  u = &User{Id: user.Id}
    //  err = Ormer.Read(u)
    //  this will find User by UserName field
    //  u = &User{UserName: "astaxie", Password: "pass"}
    //  err = Ormer.Read(u, "UserName")
    Read(md interface{}, cols ...string) error
    // Like Read(), but with "FOR UPDATE" clause, useful in transaction.
    // Some databases are not support this feature.
    ReadForUpdate(md interface{}, cols ...string) error
    // Try to read a row from the database, or insert one if it doesn't exist
    ReadOrCreate(md interface{}, col1 string, cols ...string) (bool, int64, error)
    // insert model data to database
    // for example:
    //  user := new(User)
    //  id, err = Ormer.Insert(user)
    //  user must a pointer and Insert will set user's pk field
    Insert(interface{}) (int64, error)
    // mysql:InsertOrUpdate(model) or InsertOrUpdate(model,"colu=colu+value")
    // if colu type is integer : can use(+-*/), string : convert(colu,"value")
    // postgres: InsertOrUpdate(model,"conflictColumnName") or InsertOrUpdate(model,"conflictColumnName","colu=colu+value")
    // if colu type is integer : can use(+-*/), string : colu || "value"
    InsertOrUpdate(md interface{}, colConflitAndArgs ...string) (int64, error)
    // insert some models to database
    InsertMulti(bulk int, mds interface{}) (int64, error)
    // update model to database.
    // cols set the columns those want to update.
    // find model by Id(pk) field and update columns specified by fields, if cols is null then update all columns
    // for example:
    // user := User{Id: 2}
    //  user.Langs = append(user.Langs, "zh-CN", "en-US")
    //  user.Extra.Name = "beego"
    //  user.Extra.Data = "orm"
    //  num, err = Ormer.Update(&user, "Langs", "Extra")
    Update(md interface{}, cols ...string) (int64, error)
    // delete model in database
    Delete(md interface{}, cols ...string) (int64, error)
    // load related models to md model.
    // args are limit, offset int and order string.
    //
    // example:
    //  Ormer.LoadRelated(post,"Tags")
    //  for _,tag := range post.Tags{...}
    //args[0] bool true useDefaultRelsDepth ; false  depth 0
    //args[0] int  loadRelationDepth
    //args[1] int limit default limit 1000
    //args[2] int offset default offset 0
    //args[3] string order  for example : "-Id"
    // make sure the relation is defined in model struct tags.
    LoadRelated(md interface{}, name string, args ...interface{}) (int64, error)
    // create a models to models queryer
    // for example:
    //  post := Post{Id: 4}
    //  m2m := Ormer.QueryM2M(&post, "Tags")
    QueryM2M(md interface{}, name string) QueryM2Mer
    // return a QuerySeter for table operations.
    // table name can be string or struct.
    // e.g. QueryTable("user"), QueryTable(&user{}) or QueryTable((*User)(nil)),
    QueryTable(ptrStructOrTableName interface{}) QuerySeter
    // switch to another registered database driver by given name.
    Using(name string) error
    // begin transaction
    // for example:
    //  o := NewOrm()
    //  err := o.Begin()
    //  ...
    //  err = o.Rollback()
    Begin() error
    // commit transaction
    Commit() error
    // rollback transaction
    Rollback() error
    // return a raw query seter for raw sql string.
    // for example:
    //   ormer.Raw("UPDATE `user` SET `user_name` = ? WHERE `user_name` = ?", "slene", "testing").Exec()
    //  // update user testing's name to slene
    Raw(query string, args ...interface{}) RawSeter
    Driver() Driver
}

o := orm.NewOrm()
var qs QuerySeter
qs = o.QueryTable("user")
// 如果表没有定义过，会立刻 panic

orm.RegisterDataBase("db1", "mysql", "root:root@/orm_db2?charset=utf8")
orm.RegisterDataBase("db2", "sqlite3", "data.db")

o1 := orm.NewOrm()
o1.Using("db1")

o2 := orm.NewOrm()
o2.Using("db2")

// 切换为其他数据库以后
// 这个 Ormer 对象的其下的 api 调用都将使用这个数据库

o := NewOrm()
var r RawSeter
r = o.Raw("UPDATE user SET name = ? WHERE name = ?", "testing", "slene")

type Driver interface {
    Name() string
    Type() DriverType
}

orm.RegisterDataBase("db1", "mysql", "root:root@/orm_db2?charset=utf8")
orm.RegisterDataBase("db2", "sqlite3", "data.db")

o1 := orm.NewOrm()
o1.Using("db1")
dr := o1.Driver()
fmt.Println(dr.Name() == "db1") // true
fmt.Println(dr.Type() == orm.DRMySQL) // true

o2 := orm.NewOrm()
o2.Using("db2")
dr = o2.Driver()
fmt.Println(dr.Name() == "db2") // true
fmt.Println(dr.Type() == orm.DRSqlite) // true

func main() {
    orm.Debug = true
...

var w io.Writer
...
// 设置为你的 io.Writer
...
orm.DebugLog = orm.NewLog(w)