Golang 学习笔记(10)—— mysql操作

96
ChainZhang
2018.01.04 15:43* 字数 376

本文为转载,原文:Golang 学习笔记(10)—— mysql操作

Golang

go-sql-driver/mysql

go操作mysql的驱动包很多,这里讲解当下比较流行的go-sql-driver/mysql

安装

执行下面两个命令:

go get github.com/go-sql-driver/mysql  //下载
go install github.com/go-sql-driver/mysql //安装

安装完成以后的文件截图


安装完成

安装完成

使用

package

import (
    "database/sql"
    _ "github.com/go-sql-driver/mysql"
)

数据库

在mysql中建一张测试的表,sql如下:

CREATE TABLE `userinfo` (
    `uid` INT(10) NOT NULL AUTO_INCREMENT,
    `username` VARCHAR(64) NULL DEFAULT NULL,
    `departname` VARCHAR(64) NULL DEFAULT NULL,
    `created` DATE NULL DEFAULT NULL,
    PRIMARY KEY (`uid`)
)

连接

db, err := sql.Open("mysql", "用户名:密码@tcp(IP:端口)/数据库?charset=utf8")

insert

有2种方法。

  1. 直接使用Exec函数添加
result, err := db.Exec("INSERT INTO userinfo (username, departname, created) VALUES (?, ?, ?)","chain","dev","2018-01-04")
  1. 首先使用Prepare获得stmt,然后调用Exec添加
stmt, err := db.Prepare("INSERT userinfo SET username=?,departname=?,created=?")
res, err := stmt.Exec("iris", "test", "2018-01-04")
  • 另一个经常用到的功能,获得刚刚添加数据的自增ID
id, err := res.LastInsertId()
  • 示例
package main

import (
    "time"
    "fmt"
    "database/sql"
    _ "github.com/go-sql-driver/mysql"
)

var (
    dbhost = "xxx.xxx.xxx.xxx:3306"
    dbusername = "xxxx"
    dbpassword = "xxxx"
    dbname = "xxx"
)


func main(){
    Insert("chain", "dev", "1")
    Insert("chain", "dev", "2")
    Insert("iris", "test", "1")
    Insert("iris", "test", "2")
}
/*
  获取sql.DB对象
*/
func GetDB() *sql.DB{
    db, err := sql.Open("mysql", fmt.Sprintf("%s:%s@tcp(%s)/%s?charset=utf8", dbusername, dbpassword, dbhost, dbname))
    CheckErr(err)
    return db
}

/*
  插入数据
*/
func Insert(username, departname, method string)bool{
    db := GetDB()
    defer db.Close()

    if method == "1"{
        _, err := db.Exec("insert into userinfo(username,departname,created) values(?,?,?)",username,departname,time.Now())
        if err != nil{
            fmt.Println("insert err: ", err.Error())
            return false
        }
        fmt.Println("insert success!")
        return true
    }else if method == "2"{
        stmt, err := db.Prepare("INSERT userinfo SET username=?,departname=?,created=?")
        if err != nil{
            fmt.Println("insert prepare error: ", err.Error())
            return false
        }
        _, err = stmt.Exec(username, departname, time.Now())
        if err != nil{
            fmt.Println("insert exec error: ", err.Error())
            return false
        }
        fmt.Println("insert success!")
        return true
    }
    return false
}
运行结果

数据库结果

delete

与insert所用的方法一致,只是将sql语句改为对应的功能就行。

func main(){
    Delete(15)
}
/*
  根据id删除数据
*/
func Delete(id int) bool {
    db := GetDB()
    defer db.Close()

    stmt, err := db.Prepare("delete from userinfo where uid=?")
    if err != nil{
        fmt.Println("delete prepare error: ", err.Error())
        return false
    }
    _, err = stmt.Exec(id)
    if err != nil{
        fmt.Println("delete exec error: ", err.Error())
        return false
    }
    fmt.Println("delete success!")
    return true
}
运行结果

数据库结果

update

与insert所用的方法一致,只是将sql语句改为对应的功能就行。

func main(){
    UpdateName(13,"chairis")
}
/*
  根据id,修改名称
*/
func UpdateName(id int, name string)bool{
    db := GetDB()
    defer db.Close()

    stmt, err := db.Prepare("update userinfo set username=? where uid=?")
    if err != nil{
        fmt.Println("update name prepare error: ", err.Error())
        return false
    }
    _, err = stmt.Exec(name, id)
    if err != nil{
        fmt.Println("update name exec error: ", err.Error())
        return false
    }
    fmt.Println("update name success!")
    return true
}
运行结果

数据库结果

select

  • 查询单条数据,QueryRow 函数
func main(){
    GetOne(13)
}
func GetOne(id int){
    db := GetDB()
    defer db.Close()
    var username, departname, created string
    err := db.QueryRow("select username, departname, created from userinfo where uid=?",id).Scan(&username, &departname, &created)
    if err != nil{
        fmt.Println("get one error: ", err.Error())
        return
    }
    fmt.Println("username: ", username, "departname: ", departname, "created: ", created)
}
运行结果
  • 查询多条数据,并遍历
    Query 获取数据,for xxx.Next() 遍历数据
func main(){
    GetAll()
}
func GetAll(){
    db := GetDB()
    defer db.Close()
    rows, err := db.Query("select username, departname, created from userinfo")
    if err != nil{
        fmt.Println("get all error: ", err.Error())
        return
    }
    for rows.Next(){
        var username, departname, created string
        if err := rows.Scan(&username, &departname, &created); err == nil{
            fmt.Println("username: ", username, "departname: ", departname, "created: ", created)
        }
    }
}
运行结果

事务

在操作数据库之前执行,db.Begin()
例:tx, err := db.Begin()
保存到数据库:err := tx.Commit()
回滚:err := tx.Rollback()
注意设置事务以后操作数据库就不是db了,而是tx
请看以下示例:

func main(){
    Trans()
}

func Trans(){
    db := GetDB()
    defer db.Close();

    tx, err := db.Begin()
    if err != nil{
        fmt.Println("db.Begin error: ", err.Error())
        return
    }
    isCommit := true
    defer func(){
        if isCommit{
            tx.Commit()
            fmt.Println("commit")
        }else{
            tx.Rollback()
            fmt.Println("Rollback")
        }
    }()
    _, err = tx.Exec("insert into userinfo(username,departname,created) values(?,?,?)","username","departname",time.Now())
    if err != nil{
        isCommit = false
    }
    _, err = tx.Exec("insert into userinfo(username,departname,created) values(?,?,?)","username","departname",time.Now())
    if err != nil{
        isCommit = false
    }
    _, err = tx.Exec("insert into userinfo(username,departname,created) values(?,?,?)","username","departname",time.Now())
    if err != nil{
        isCommit = false
    }
}
运行结果

全部代码

package main

import (
    "time"
    "fmt"
    "database/sql"
    _ "github.com/go-sql-driver/mysql"
)

var (
    dbhost = "xxx.xxx.xxx.xxx:3306"
    dbusername = "xxxxxx"
    dbpassword = "xxxxxx"
    dbname = "xxxxxx"
)


func main(){
    Trans()
}

func Trans(){
    db := GetDB()
    defer db.Close();

    tx, err := db.Begin()
    if err != nil{
        fmt.Println("db.Begin error: ", err.Error())
        return
    }
    isCommit := true
    defer func(){
        if isCommit{
            tx.Commit()
            fmt.Println("commit")
        }else{
            tx.Rollback()
            fmt.Println("Rollback")
        }
    }()
    _, err = tx.Exec("insert into userinfo(username,departname,created) values(?,?,?)","username","departname",time.Now())
    if err != nil{
        isCommit = false
    }
    _, err = tx.Exec("insert into userinfo(username,departname,created) values(?,?,?)","username","departname",time.Now())
    if err != nil{
        isCommit = false
    }
    _, err = tx.Exec("insert into userinfo(username,departname,created) values(?,?,?)","username","departname",time.Now())
    if err != nil{
        isCommit = false
    }
}

/*
  获取sql.DB对象
*/
func GetDB() *sql.DB{
    db, err := sql.Open("mysql", fmt.Sprintf("%s:%s@tcp(%s)/%s?charset=utf8", dbusername, dbpassword, dbhost, dbname))
    CheckErr(err)
    return db
}

/*
  插入数据
*/
func Insert(username, departname, method string)bool{
    db := GetDB()
    defer db.Close()

    if method == "1"{
        _, err := db.Exec("insert into userinfo(username,departname,created) values(?,?,?)",username,departname,time.Now())
        if err != nil{
            fmt.Println("insert err: ", err.Error())
            return false
        }
        fmt.Println("insert success!")
        return true
    }else if method == "2"{
        stmt, err := db.Prepare("INSERT userinfo SET username=?,departname=?,created=?")
        if err != nil{
            fmt.Println("insert prepare error: ", err.Error())
            return false
        }
        _, err = stmt.Exec(username, departname, time.Now())
        if err != nil{
            fmt.Println("insert exec error: ", err.Error())
            return false
        }
        fmt.Println("insert success!")
        return true
    }
    return false
}

/*
  根据id,修改名称
*/
func UpdateName(id int, name string)bool{
    db := GetDB()
    defer db.Close()

    stmt, err := db.Prepare("update userinfo set username=? where uid=?")
    if err != nil{
        fmt.Println("update name prepare error: ", err.Error())
        return false
    }
    _, err = stmt.Exec(name, id)
    if err != nil{
        fmt.Println("update name exec error: ", err.Error())
        return false
    }
    fmt.Println("update name success!")
    return true
}

/*
  根据id删除数据
*/
func Delete(id int) bool {
    db := GetDB()
    defer db.Close()

    stmt, err := db.Prepare("delete from userinfo where uid=?")
    if err != nil{
        fmt.Println("delete prepare error: ", err.Error())
        return false
    }
    _, err = stmt.Exec(id)
    if err != nil{
        fmt.Println("delete exec error: ", err.Error())
        return false
    }
    fmt.Println("delete success!")
    return true
}

func GetOne(id int){
    db := GetDB()
    defer db.Close()
    var username, departname, created string
    err := db.QueryRow("select username, departname, created from userinfo where uid=?",id).Scan(&username, &departname, &created)
    if err != nil{
        fmt.Println("get one error: ", err.Error())
        return
    }
    fmt.Println("username: ", username, "departname: ", departname, "created: ", created)
}

func GetAll(){
    db := GetDB()
    defer db.Close()
    
    rows, err := db.Query("select username, departname, created from userinfo")
    if err != nil{
        fmt.Println("get all error: ", err.Error())
        return
    }
    for rows.Next(){
        var username, departname, created string
        if err := rows.Scan(&username, &departname, &created); err == nil{
            fmt.Println("username: ", username, "departname: ", departname, "created: ", created)
        }
    }
    
}

func CheckErr(err error){
    if err != nil{
        fmt.Println("err: ", err.Error())
        panic(err)
    }
}

源码

github 源码地址

转载请注明出处:
Golang 学习笔记(10)—— mysql操作

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