Go操作MySQL总结

1.下载驱动包

打开GoLand—>Terminal，输入：go get github.com/go-sql-driver/mysql

2.编写代码

package main

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

//数据库连接信息
const (
   USERNAME = "root"
   PASSWORD = "123456"
   NETWORK  = "tcp"
   SERVER   = "localhost"
   PORT     = 3306
   DATABASE = "test"
)

//user表结构体定义
type User struct {
   Id         int    `json:"id" form:"id"`
   Username   string `json:"username" form:"username"`
   Password   string `json:"password" form:"password"`
   Status     int    `json:"status" form:"status"` // 0 正常状态， 1删除
   Createtime int64  `json:"createtime" form:"createtime"`
}

func main() {
   conn := fmt.Sprintf("%s:%s@%s(%s:%d)/%s", USERNAME, PASSWORD, NETWORK, SERVER, PORT, DATABASE)
   DB, err := sql.Open("mysql", conn)
   if err != nil {
      fmt.Println("connection to mysql failed:", err)
      return
   }

   DB.SetConnMaxLifetime(100 * time.Second) //最大连接周期，超时的连接就close
   DB.SetMaxOpenConns(100)                  //设置最大连接数
   CreateTable(DB)
   InsertData(DB)
   QueryOne(DB)
   QueryMulti(DB)
   UpdateData(DB)
   DeleteData(DB)
}

//创建表
func CreateTable(DB *sql.DB) {
   sql := `CREATE TABLE IF NOT EXISTS users(
   id INT(4) PRIMARY KEY AUTO_INCREMENT NOT NULL,
   username VARCHAR(64),
   password VARCHAR(64),
   status INT(4),
   createtime INT(10)
   ); `

   if _, err := DB.Exec(sql); err != nil {
      fmt.Println("create table failed:", err)
      return
   }
   fmt.Println("create table successd")
}

//添加数据
func InsertData(DB *sql.DB) {
   result, err := DB.Exec("insert INTO users(username,password) values(?,?)", "test", "123456")
   if err != nil {
      fmt.Printf("Insert data failed,err:%v", err)
      return
   }
   lastInsertID, err := result.LastInsertId() //获取插入数据的自增ID
   if err != nil {
      fmt.Printf("Get insert id failed,err:%v", err)
      return
   }
   fmt.Println("Insert data id:", lastInsertID)

   rowsaffected, err := result.RowsAffected() //通过RowsAffected获取受影响的行数
   if err != nil {
      fmt.Printf("Get RowsAffected failed,err:%v", err)
      return
   }
   fmt.Println("Affected rows:", rowsaffected)
}

//查询单行
func QueryOne(DB *sql.DB) {
   user := new(User) //用new()函数初始化一个结构体对象
   row := DB.QueryRow("select id,username,password from users where id=?", 2)
   //row.scan中的字段必须是按照数据库存入字段的顺序，否则报错
   if err := row.Scan(&user.Id, &user.Username, &user.Password); err != nil {
      fmt.Printf("scan failed, err:%v\n", err)
      return
   }
   fmt.Println("Single row data:", *user)
}

//查询多行
func QueryMulti(DB *sql.DB) {
   user := new(User)
   rows, err := DB.Query("select id,username,password from users where id = ?", 2)

   defer func() {
      if rows != nil {
         rows.Close() //关闭掉未scan的sql连接
      }
   }()
   if err != nil {
      fmt.Printf("Query failed,err:%v\n", err)
      return
   }
   for rows.Next() {
      err = rows.Scan(&user.Id, &user.Username, &user.Password) //不scan会导致连接不释放
      if err != nil {
         fmt.Printf("Scan failed,err:%v\n", err)
         return
      }
      fmt.Println("scan successd:", *user)
   }
}

//更新数据
func UpdateData(DB *sql.DB) {
   result, err := DB.Exec("UPDATE users set password=? where id=?", "111111", 3)
   if err != nil {
      fmt.Printf("Insert failed,err:%v\n", err)
      return
   }
   fmt.Println("update data successd:", result)

   rowsaffected, err := result.RowsAffected()
   if err != nil {
      fmt.Printf("Get RowsAffected failed,err:%v\n", err)
      return
   }
   fmt.Println("Affected rows:", rowsaffected)
}

//删除数据
func DeleteData(DB *sql.DB) {
   result, err := DB.Exec("delete from users where id=?", 2)
   if err != nil {
      fmt.Printf("Insert failed,err:%v\n", err)
      return
   }
   fmt.Println("delete data successd:", result)

   rowsaffected, err := result.RowsAffected()
   if err != nil {
      fmt.Printf("Get RowsAffected failed,err:%v\n", err)
      return
   }
   fmt.Println("Affected rows:", rowsaffected)
}