Eli's Blog

1. 入门

1.1 安装

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go get -u github.com/jinzhu/gorm

1.2 驱动

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import _ "github.com/jinzhu/gorm/dialects/mysql"
import _ "github.com/jinzhu/gorm/dialects/postgres"
import _ "github.com/jinzhu/gorm/dialects/sqlite"
import _ "github.com/jinzhu/gorm/dialects/mssql"

2. 操作

2.1 表结构定义

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type Admin struct {
	ID       int64
	Username string `gorm:"size:50;not null"`
	Password string `gorm:"size:128"`
}

type Account struct {
	gorm.Model // ID, CreatedAt, UpdatedAt, DeletedAt

	Appkey  string `gorm:"type:varchar(15);index:idx_appkey;not null"`
	Company string `gorm:"column:company_name;size:30"`
	Status  int8   `gorm:"default:1"`
}

func (Admin) TableName() string {
	return "tbl_admin"
}

func (Account) TableName() string {
	return "tbl_account"
}

2.2 连接数据库

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const (
	DBUSER = "root"
	DBPASS = ""
	HOST   = "127.0.0.1"
	PORT   = "3306"
	DBNAME = "blog"
)

func GetConn() *gorm.DB {
	connStr := fmt.Sprintf("%s:%s@tcp(%s:%s)/%s?charset=utf8&parseTime=True&loc=Local&timeout=10ms",
		DBUSER, DBPASS, HOST, PORT, DBNAME)
	fmt.Println(connStr)

	db, err := gorm.Open("mysql", connStr)
	if err != nil {
		log.Fatalf("mysql connect error: %v", err)
	}

	db.DB().SetMaxIdleConns(10)
	db.DB().SetMaxOpenConns(100)

	// 自动创建和更新表结构
	if !db.HasTable("tbl_admin") {
		db.Set("gorm:table_options", "ENGINE=InnoDB").AutoMigrate(&Admin{})
	}

	if !db.HasTable("tbl_account") {
		db.Set("gorm:table_options", "ENGINE=InnoDB").AutoMigrate(&Account{})
	}

	return db
}

2.3 新增数据

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func Insert(db *gorm.DB) {
	c := make(chan Admin)

	go generateData(c)

	for v := range c {
		db.NewRecord(v) // 检查主键是否存在
		db.Create(&v)
	}
}

func generateRandomString(n int) string {
	s := "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890_"
	bs := make([]byte, n)
	for i := 0; i < n; i++ {
		bs[i] = s[rand.Intn(len(s))]
	}

	return string(bs)
}

func md5Encrypt(s string) string {
	return fmt.Sprintf("%x", md5.Sum([]byte(s)))
}

func generateData(c chan Admin) {
	for i := 0; i < 20; i++ {
		name := generateRandomString(6)
		pass := md5Encrypt(name + "_123456")
		c <- Admin{Username: name, Password: pass}
	}

	close(c)
}

2.4 查询数据

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func Select(db *gorm.DB) {
	a := Admin{}
	db.Select([]string{"id", "username", "password"}).Where("id = ?", 1).First(&a)
	fmt.Println(a)
}

func SelectMany(db *gorm.DB) {
	as := []Admin{}
	db.Where("username like '%4%'").Find(&as)
	for _, a := range as {
		fmt.Println(a)
	}
}

2.5 更新数据

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func Update(db *gorm.DB) {
	a := Admin{}
	db.Where("id = ?", 1).First(&a)
	a.Username = "elihe123"
	a.Password = md5Encrypt("123456")
	db.Save(a) // 数据必须有变化，否则无法保存

	b := Admin{
		ID:       30,
		Username: "rania123",
		Password: md5Encrypt("654321"),
	}
	db.Save(b) // id不存在时，自动创建

	c := Admin{ID: 10}
	db.Model(&c).Update("username", "eli")
}

2.6 删除数据

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func Delete(db *gorm.DB) {
	a := Admin{ID: 30}
	db.Delete(&a)
}

3. 钩子函数(callbacks)

  • 创建: BeforeSave, BeforeCreate, AfterCreate, AfterSave
  • 更新: BeforeSave, BeforeUpdate, AfterUpdate, AfterSave
  • 删除: BeforeDelete, AfterDelete
  • 查询: AfterFind
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func (Account) BeforeCreate(scope *gorm.Scope) error {
	scope.SetColumn("CreatedAt", time.Now().Unix())
	return nil
}

func (Account) BeforeUpdate(scope *gorm.Scope) error {
	scope.SetColumn("UpdatedAt", time.Now().Unix())
	return nil
}

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