1. 简单示例

db.Create(&liuBei)

• 完整示例

package main

import (
    "database/sql"
    "fmt"
    "gorm.io/driver/mysql"
    "gorm.io/gorm"
    "time"
)

type User struct {
    ID int64
    Age int64
    Name string
}

func main() {
    db,sqlDB,_ := connect()
    defer sqlDB.Close()
    liuBei := User{
        Name: "LiuBei",
        Age: 28,
    }
    db.Create(&liuBei)

}

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

2. 用指定的字段创建记录

• 使用指定字段

db.Select("name").Create(&liuBei)

• 排除指定字段

db.Omit("name").Create(&liuBei)

3. 批量插入

3.1 用数组切片创建

func main() {
    db,sqlDB,_ := connect()
    defer sqlDB.Close()

    var users = []User{{Name: "LiuBei",Age: 28}, {Name: "GuanYu",Age: 22}, {Name: "ZhangFei",Age: 20}}
    db.Create(&users)
    fmt.Println(users)

}

• 输出

OK
[{8 28 LiuBei} {9 22 GuanYu} {10 20 ZhangFei}]

• 数据库表结果

mysql> select * from users;
+----+------+----------+
| id | age  | name     |
+----+------+----------+
|  8 |   28 | LiuBei   |
|  9 |   22 | GuanYu   |
| 10 |   20 | ZhangFei |
+----+------+----------+
3 rows in set (0.00 sec)

3.2 CreateInBatches 批量创建

测试未成功，依然会创建5条数据。

func main() {
    db,sqlDB,_ := connect()
    defer sqlDB.Close()

    //db.Migrator().CreateTable(&User{})
    user := []User{{Name: "soldier_01"},{Name: "soldier_02"},{Name: "soldier_03"},{Name: "soldier_04"},{Name: "soldier_05"}}
    db.CreateInBatches(user, 3)
}

4. 创建钩子

4.1 概念

• GORM 允许用户定义的钩子
  BeforeSave, BeforeCreate,AfterSave, AfterCreate

• 创建

func (u *User) BeforeCreate(tx *gorm.DB) (err error) {
    u.Name = "Shi_Bing"
    return
}

4.2 完整示例

• 代码

示例中通过切片创建表，本应是 soldier_01到soldier_05。但因为 BeforeCreate方法的存在，实际表中name列都是 shi_bing

package main

import (
    "database/sql"
    "fmt"
    "gorm.io/driver/mysql"
    "gorm.io/gorm"
    "time"
)

type User struct {
    ID int64
    Age int64
    Name string
}

func (u *User) BeforeCreate(tx *gorm.DB) (err error) {
    u.Name = "Shi_Bing"
    return
}


func main() {
    db,sqlDB,_ := connect()
    defer sqlDB.Close()
    user := []User{{Name: "soldier_01"},{Name: "soldier_02"},{Name: "soldier_03"},{Name: "soldier_04"},{Name: "soldier_05"}}
    db.Create(&user)
    fmt.Println(user)
}

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

• 输出

OK
[{16 0 Shi_Bing} {17 0 Shi_Bing} {18 0 Shi_Bing} {19 0 Shi_Bing} {20 0 Shi_Bing}]

• 数据库表

mysql> select * from users;
+----+------+----------+
| id | age  | name     |
+----+------+----------+
| 16 |    0 | Shi_Bing |
| 17 |    0 | Shi_Bing |
| 18 |    0 | Shi_Bing |
| 19 |    0 | Shi_Bing |
| 20 |    0 | Shi_Bing |
+----+------+----------+
5 rows in set (0.00 sec)

4.3 跳过钩子

SkipHooks 会话模式可以跳过钩子。

db.Session(&gorm.Session{SkipHooks: true}).Create(&user)

5. 根据MAP 创建

    user := map[string]interface{}{
        "Name":"GuanYu",
        "Age":22,
    }
    db.Model(&User{}).Create(user)