[大数据]ORM框架Gorm-更新记录

用户结构体

type User struct {
	gorm.Model
	Name     string
	Age      int
	Birthday time.Time
	Active   bool
}

给原来的数据库添加字段

db.AutoMigrate(&User{})

保存所有字段

func update1() {
	var user User
	db.First(&user)
	fmt.Printf("user: %v\n", user)
	user.Name = "x王帆"
	user.Active = true
	db.Save(&user)
	fmt.Printf("user: %v\n", user)
}

运行结果：
数据库数据如下：

更新单个列

条件更新

	db.Model(&User{}).Where("active = ?", true).Update("Name", "hello")
	// UPDATE `users` SET `name`='hello',`updated_at`='2022-03-10 15:41:00.917' WHERE active = true AND `users`.`deleted_at` IS NULL

运行后数据数据：

查出需要更新的

var user User
db.First(&user)
db.Model(&user).Update("name", "hello--wf")
//UPDATE `users` SET `name`='hello--wf',`updated_at`='2022-03-10 15:43:24.55' WHERE `users`.`deleted_at` IS NULL AND `id` = 1

根据条件和model的值进行更新

var user User
	// db.First(&user)
	db.First(&user, 2)
	db.Model(&user).Where("active = ?", true).Update("name", "hello-true")
	// UPDATE `users` SET `name`='hello-true',`updated_at`='2022-03-10 15:44:50.555' WHERE active = true AND `users`.`deleted_at` IS NULL AND `id` = 1
	// UPDATE `users` SET `name`='hello-true',`updated_at`='2022-03-10 15:45:30.254' WHERE active = true AND `users`.`deleted_at` IS NULL AND `id` = 2

数据库运行结果：(因为id为2的数据的active是false所以id为2的数据name没更新)

更新多列

根据struct更新属性，只会更新非零值得字段

var user User
	db.First(&user)
	db.Model(&user).Updates(User{Name: "hello", Age: 18, Active: false})
	// UPDATE `users` SET `updated_at`='2022-03-10 15:53:15.957',`name`='hello',`age`=18 WHERE `users`.`deleted_at` IS NULL AND `id` = 1

注意观察 active没有变为false

根据map更新属性

var user User
	db.First(&user)
	db.Model(&user).Updates(map[string]interface{}{"name": "hello", "age": 18, "active": false})
	// UPDATE `users` SET `active`=false,`age`=18,`name`='hello',`updated_at`='2022-03-10 16:08:59.393' WHERE `users`.`deleted_at` IS NULL AND `id` = 1

注意观察active变为false了

更新选定字段

更新时候选定、忽略某些字段，可以使用select、omit

使用map进行select更新选择字段

var user User
db.First(&user)
db.Model(&user).Select("name").Updates(map[string]interface{}{"name": "hello-1", "age": 18, "active": false})
// UPDATE `users` SET `name`='hello-1',`updated_at`='2022-03-10 17:07:06.834' WHERE `users`.`deleted_at` IS NULL AND `id` = 1

使用map进行omit更新忽略字段

var user User
	db.First(&user)
	db.Model(&user).Omit("name").Updates(map[string]interface{}{"name": "hello-1", "age": 180, "active": false})
	// UPDATE `users` SET `active`=false,`age`=180,`updated_at`='2022-03-10 17:08:06.567' WHERE `users`.`deleted_at` IS NULL AND `id` = 1

使用 Struct 进行 Select（会 select 零值的字段）

var user User
db.First(&user)
db.Model(&user).Select("Name", "Age").Updates(User{Name: "new_name", Age: 0})
// UPDATE `users` SET `updated_at`='2022-03-10 17:11:57.372',`name`='new_name',`age`=0 WHERE `users`.`deleted_at` IS NULL AND `id` = 1

// Select 所有字段（查询包括零值字段的所有字段）
db.Model(&user).Select("*").Update(User{Name: "jinzhu", Role: "admin", Age: 0})

// Select 除 Role 外的所有字段（包括零值字段的所有字段）
db.Model(&user).Select("*").Omit("Role").Update(User{Name: "jinzhu", Role: "admin", Age: 0})

更新hook

func (u *User) BeforeUpdate(tx *gorm.DB) (err error) {
	fmt.Println("BeforeUpdate")
	return
}

批量更新

根据struct更新

db.Model(User{}).Select("Name", "Age").Where("id IN ?", []int{5, 6}).Updates(User{Name: "hello", Age: 20})
// UPDATE `users` SET `updated_at`='2022-03-10 17:31:29.921',`name`='hello',`age`=20 WHERE id IN (5,6) AND `users`.`deleted_at` IS NULL

根据map更新

db.Table("users").Where("id IN ?", []int{6, 7}).Updates(map[string]interface{}{"name": "hello1", "age": 19})
// UPDATE `users` SET `age`=19,`name`='hello1' WHERE id IN (6,7)

参考链接

https://gorm.io/zh_CN/docs/update.html