MYSQL 悲观锁

tx := db.DB.Begin()
if err := tx.Set("gorm:query_option", "FOR UPDATE").
Where("`xx` = ? and `xxx` = ?", xx, xxx).
First(&xx).Error; err != nil {
tx.Rollback()
return
}

在事务中使用 Set("gorm:query_option", "FOR UPDATE") + first 能将查询的这条记录锁住；
在事务 rollback 或 commit 后会 unlock。

创建复合主键(当主键涉及自增时)

gorm:"primary_key;AUTO_INCREMENT:false"

连接数据库

步骤分析

  • 引入mysql数据库驱动
  • 引入gorm包
  • 读取配置文件中的数据库信息
  • 将读取的数据生成为Open()需要的字符串

代码示例

package base

import (
	_ "github.com/go-sql-driver/mysql"
	_ "github.com/jinzhu/gorm/dialects/mysql"
	"github.com/jinzhu/gorm"
	"fmt"
	"log"
)

var (
	DB       *gorm.DB
	user     = "user"
	password = "password"
	dbname   = "dbname"
	address  = "address"
	port     = "port"
)

func DBConnect() {
	dsn := fmt.Sprintf("%s:%s@tcp(%s:@s)/%s?charset=utf8&parseTime=True&loc=Local",
		user,
		password,
		address,
		port,
		dbname)
	var err error
	DB, err = gorm.Open("mysql", dsn)
	//"user:password@/dbname?charset=utf8&parseTime=True&loc=Local"
	if err != nil {
		log.Faltal("Opening mysql error is :", err)
	}
}