golang之数据库操作

1.导入必要的包

import("database/sql"_ "github.com/go-sql-driver/mysql" //使用此作为数据库驱动
)

2.相关操作

连接数据库

使用sql.Open()函数进行数据库的连接

 db, err := sql.Open("mysql", "user:password@tcp(127.0.0.1:3306)/dbname")
//用户名:密码@tcp(127.0.0.1:3306)/你要连接的数据库if err != nil {panic(err)}defer db.Close()
//使用完毕后不要忘了关闭

package mainimport("database/sql"_ "github.com/go-sql-driver/mysql""fmt"
)func main(){db,err :=sql.Open("mysql","root:123456@tcp(127.0.0.1:3306)/mydb")//db是 *sql.DB 使用Open函数打开目标的IP的指定数据库if err !=nil {fmt.Println("open error")return }fmt.Printf("type is %T\n",db)err = db.Ping()//Ping一下 看是否真的连接成功
if err != nil {panic(err)
}
fmt.Println("Connected to database!")defer db.Close()
}

运行可能出现如下错误：说明数据库拒绝访问，需要使用mysql_native_password插件。

解决上面问题执行如下SQL语句：

ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY yourpass;
//上面输入你的密码
FLUSH PRIVILEGES;

SQL查询

先执行如下SQL语句创建表和填入方法

create table user ( uid int primary key auto_increment,name varchar(20) default '', 
phone varchar(20) default '') engine=innodb;insert into user(name,phone) values('a','111'),('b','222'),('c','333');

1).使用QueryRow()方法进行单行查询

func (db* DB) QueryRow(query string,args ...interface{}) *Row
此方法执行一次 最多只能返回一行数据 并且直到返回值的Scan()方法被调用后才会返回
被延迟的错误，不推荐使用

package main
import("database/sql"_ "github.com/go-sql-driver/mysql""fmt"
)type User struct {Uid intName stringPhone string
}func main(){db,err :=sql.Open("mysql","root:123456@tcp(127.0.0.1:3306)/mydb")if err !=nil {fmt.Println("open error")return }fmt.Printf("type is %T\n",db)err = db.Ping()
if err != nil {panic(err)
}
fmt.Println("Connected to database!")defer db.Close()user1 :=User{}
err =db.QueryRow("select uid,name,phone from user where uid=2").Scan(&user1.Uid,&user1.Name,&user1.Phone)if err !=nil {fmt.Println("sql Query error")return}fmt.Println(user1.Uid," ",user1.Name," ",user1.Phone)
}

2)Query()查询多行结果

user1 :=User{}
rows ,err :=db.Query("select uid,name,phone from user")//返回error和 *rowsif err !=nil {fmt.Println("sql Query error")return}defer rows.Close()//关闭ROWS 释放所有的数据库连接//循环读取结果集中的数据 储存在结构体中for rows.Next(){err =rows.Scan(&user1.Uid,&user1.Name,&user1.Phone)if err !=nil {fmt.Println("Scan error")return}fmt.Println(user1.Uid," ",user1.Name," ",user1.Phone)}

3). db.Exec(sql string) (Result,error)可以进行表数据的增删改 .

result,err :=db.Exec("insert into user(name,phone) values('d','444')")//SQL中的字符串类型用单引号  函数执行返回(result,error)类型
if err !=nil {fmt.Println("insert error")return
}lastInsertID, err := result.LastInsertId()//获得插入数据的主键部分if err !=nil {fmt.Println("get ID error")return}fmt.Println("insert success, the id is ",lastInsertID)//剩下的删和该是一样的

4）事务操作

begin()方法开启事务：func (db *DB) Begin() (*Tx,error)

Commint()提交事务: func (tx *Tx) commit () error

Rollback()回滚事务: func (tx *Tx) Rollback() error

package main
import("database/sql"_ "github.com/go-sql-driver/mysql""fmt"
)type User struct {Uid intName stringPhone string
}func main(){db,err :=sql.Open("mysql","root:123456@tcp(127.0.0.1:3306)/mydb")if err !=nil {return }err = db.Ping()
if err != nil {panic(err)
}fmt.Println("Connected to database!")defer db.Close()tx, err :=db.Begin() //开启事务if err!=nil {if tx!=nil {tx.Rollback()}fmt.Println("begin trans failed")return }_,err1 :=tx.Exec("update user set name = 'ggg' where phone = '444'")if err1 !=nil {tx.Rollback()//执行失败 进行回滚事务fmt.Println("sal update failed")return}tx.Commit()//提交事务fmt.Println("exec transaction success!")
}