golang实现mysql数据库事务的提交与回滚

"github.com/jmoiron/sqlx"
_ "github.com/go-sql-driver/mysql"

package main 
import (
 "fmt"
 "github.com/alecthomas/log4go"
 _ "github.com/go-sql-driver/mysql"
 "github.com/jmoiron/sqlx"
)
 
var Db *sqlx.DB 
func init()  {
 db,err:=sqlx.Open("mysql","TigerwolfC:123456@tcp(127.0.0.1:3306)/test?charset=utf8")
 if err != nil {
  fmt.Println("open mysql failed,", err)
  return
 }
 Db = db
}
 
func main()  {
 mysqlTest()
} 
 
func mysqlTest() error{
 tx, err := Db.Begin()
 if err != nil {
  log4go.Error("open mysql database fail", err)
  return err
 }
 
 result, err := tx.Exec("INSERT INTO userinfo (username, password,department,email) VALUES (?, ?,?,?)","cici","33333","it","TigerwolfC@163.com")
 if err != nil{
  fmt.Println("insert failed,error： ", err)
  tx.Rollback()
  return err
 }
 id,_ := result.LastInsertId()
 fmt.Println("insert id is :",id)
 _, err = tx.Exec("update userinfo set department = ? where username = ?","cekong","hahah")
 if err != nil{
  fmt.Println("update failed error:",err)
  tx.Rollback()
  return err
 } else {
  fmt.Println("update success!")
 }
 _, err = tx.Exec("delete from userinfo where username = ? ", "weiwei")
 if err != nil{
  fmt.Println("delete error:",err)
  tx.Rollback()
  return err
 }else{
  fmt.Println("delete success")
 }
 return tx.Commit()
}

func mysqlTest() error{
 tx, err := Db.Begin()
 if err != nil {
  log4go.Error("open mysql database fail", err)
 }
 defer tx.Rollback()
 
 result, err := tx.Exec("INSERT INTO userinfo (username, password,department,email) VALUES (?, ?,?,?)","cici","33333","it","TigerwolfC@163.com")
 if err != nil{
  fmt.Println("insert failed,error： ", err)
  return err
 }
 id,_ := result.LastInsertId()
 fmt.Println("insert id is :",id)
 _, err = tx.Exec("update userinfo set department = ? where username = ?","cekong","hahah")
 if err != nil{
  fmt.Println("update failed error:",err)
  return err
 } else {
  fmt.Println("update success!")
 }
 _, err = tx.Exec("delete from userinfo where username = ? ", "weiwei")
 if err != nil{
  fmt.Println("delete error:",err)
  return err
 }else{
  fmt.Println("delete success")
 }
 return tx.Commit()
}

//数据库连接池
var db *sql.DB
//初始化数据库
func initDB() (err error){
	fmt.Println("学习数据库")
	dsn := "usename:password@tcp(127.0.0.1:3306)/dataname"
	db, err = sql.Open("mysql",dsn)
	if err!=nil {
		fmt.Println("打开数据库失败 err:",err,".dsn:",dsn)
		return
	}
	err = db.Ping()
	if err!=nil {
		fmt.Println("open failed err:",err)
		return
	}
	fmt.Println("连接数据库成功")
 
	//最大连接数
	db.SetMaxOpenConns(10)
	//设置连接池中的最大闲置连接数
	db.SetMaxIdleConns(10)
	return
}
 
func trans()  {
	tx, err := db.Begin()
	if err!=nil {
		fmt.Println("事务开启失败, err:",err)
		return
	}
	sqlStr1 := "update student set age=age-2 where id=1;"
	sqlStr2 := "update student set age=age+2 where id=3;"
	_, err = tx.Exec(sqlStr1)
	if err!=nil {
		fmt.Println("修改失败, err",err,",sqlStr1:",sqlStr1)
		tx.Rollback()
		return
	}
 
	_, err = tx.Exec(sqlStr2)
	if err!=nil {
		fmt.Println("修改失败, err",err,",sqlStr2:",sqlStr2)
		tx.Rollback()
		return
	}
 
	fmt.Println("执行成功")
	//提交事务
	tx.Commit()
}
func main() {
	fmt.Println("mysql 002.事务处理")
	initDB()
	trans() 
}