10-grom-07-删除

1. 删除记录2. 批量删除3. 软删除

db.Delete(&xiShu{ID: 2})

完整示例

删除id=2 的一行

package main

import (
	"fmt"
	"github.com/jinzhu/gorm"
	_ "github.com/jinzhu/gorm/dialects/mysql"
)
type xiShu struct {
	ID int64
	Name string
	Age int64
}

func(xiShu) TableName() string {
	return "xi_shu"
}

func main() {

	db,_ := connect()
	defer db.Close()
	result := db.Delete(&xiShu{ID: 2})
	fmt.Println(result.Value)
}

func connect() (db *gorm.DB,err error) {
	db, err = gorm.Open("mysql", "root:40010355@tcp(127.0.0.1:3306)/crow?charset=utf8&parseTime=True&loc=Local")
	if err != nil {
		fmt.Printf(err.Error())
		defer db.Close()
	}else {
		fmt.Printf("OKn")
		db.DB().SetMaxIdleConns(10)
		db.DB().SetMaxOpenConns(100)
	}
	return
}

db.Where("name LIKE ?", "%Guan%").Delete(&xiShu{})

或写作

db.Delete(xiShu{},"name LIKE ?","%Guan%")

示例
表中原有数据

mysql> select * from xi_shu ;
+----+------------+------+
| id | name       | age  |
+----+------------+------+
|  1 | LiuBei     |   28 |
|  2 | GuanYu     |   22 |
|  3 | ZhangFei   |   20 |
|  4 | ZhaoYun    |   18 |
|  5 | ZhuGeLiang |   20 |
|  6 | GuanPing   |    3 |
+----+------------+------+
6 rows in set (0.00 sec)

代码

上例main函数修改如下：

func main() {
	db,_ := connect()
	defer db.Close()
	result := db.Where("name LIKE ?", "%Guan%").Delete(&xiShu{}).RowsAffected
	fmt.Println(result)
}

表修改后

mysql> select * from xi_shu ;
+----+------------+------+
| id | name       | age  |
+----+------------+------+
|  1 | LiuBei     |   28 |
|  3 | ZhangFei   |   20 |
|  4 | ZhaoYun    |   18 |
|  5 | ZhuGeLiang |   20 |
+----+------------+------+
4 rows in set (0.00 sec)

如上，关家将都被删除

实际是给deleted_at列加了一个删除时间deleted_at列必须存在，否则直接删除

db.Delete(&xiShu{ID: 2})

示例

package main

import (
	"fmt"
	"github.com/jinzhu/gorm"
	_ "github.com/jinzhu/gorm/dialects/mysql"
	"time"
)
type xiShu struct {
	ID int64
	Name string
	Age int64
	DeletedAt time.Time
}

func(xiShu) TableName() string {
	return "xi_shu"
}


func main() {

	db,_ := connect()
	defer db.Close()
	result := db.Delete(&xiShu{ID: 2}).RowsAffected
	fmt.Println(result)
}

func connect() (db *gorm.DB,err error) {
	db, err = gorm.Open("mysql", "root:40010355@tcp(127.0.0.1:3306)/crow?charset=utf8&parseTime=True&loc=Local")
	if err != nil {
		fmt.Printf(err.Error())
		defer db.Close()
	}else {
		fmt.Printf("OKn")
		db.DB().SetMaxIdleConns(10)
		db.DB().SetMaxOpenConns(100)
	}
	return
}

执行后表格

mysql> select * from xi_shu ;
+----+----------+------+---------------------+
| id | name     | age  | deleted_at          |
+----+----------+------+---------------------+
|  1 | LiuBei   |   28 | NULL                |
|  2 | GuanYu   |   22 | 2022-02-10 14:39:56 |
|  3 | ZhangFei |   20 | NULL                |
+----+----------+------+---------------------+
3 rows in set (0.00 sec)

如上可见，第二行没有被真正删除，只是在deleted_at列加了删除的时间