Golang mysql使用举例---连接本地数据库

- 日理万妓 2022-05-06 10:56 285阅读 0赞

连接数据库的方式有两种：TCP和Unix域socket。  
本文使用Unix domain sockets连接数据库。关于TCP连接数据库可以参考[Go 操作mysql使用举例][Go _mysql]

下面例子中，演示了使用show命令查看数据库连接信息的过程。  
show processlist可以查看当前时刻数据库的连接以及正在执行的sql语句。

代码如下：

package main
    
    import (
    	"database/sql"
    	"fmt"
    	"log"
    
    	_ "github.com/go-sql-driver/mysql"
    
    )
    
    type DBConnectionInfo struct {
    	ID	[]byte
    	User	string
    	Host	string
    	DB	[]byte 
    	Cmd	string
    	Time	[]byte
    	State	string
    	Info	[]byte
    }
    
    func(f *DBConnectionInfo) String() string{
    
    	return fmt.Sprintf("ID:%s, User:%s, Host:%s, DB:%s, Cmd:%s, Time:%s, State:%s, Info:%s", string(f.ID), f.User, f.Host, string(f.DB), f.Cmd, string(f.Time), f.State, string(f.Info))
    
    }
    
    const (
    	mysqlShowProcessList="show processlist"
    )
    var DB *sql.DB
    
    //var dataBase = "root:Aa123456@unix(/tmp/mysql.sock)/mysql"
    var dataBase = "root:Aa123456@unix(/tmp/mysql.sock)/"
    
    func Init() {
    	var err error
    	DB, err = sql.Open("mysql", dataBase)
    	if err != nil {
    		log.Fatalln("open db fail:", err)
    	}
    
    	err = DB.Ping()
    	if err != nil {
    		log.Fatalln("ping db fail:", err)
    	}
    }
    
    func main() {
    
    	Init()
    
    	query()
    
    }
    
    
    func query() {
    
    	rows, err := DB.Query(mysqlShowProcessList)
    	if err != nil {
    		log.Println("query failed:", err)
    		return
    	}
    	defer rows.Close()
    
    	for rows.Next(){
    		data := &DBConnectionInfo{}
    		if err := rows.Scan(&data.ID, &data.User, &data.Host, &data.DB, &data.Cmd, &data.Time, &data.State, &data.Info); err != nil {
    			log.Println("Scan failed:", err)
    		}
    
    		fmt.Println("data:", data)
    	}
    
    
    }

output:

> data: ID:145, User:root, Host:localhost, DB:, Cmd:Sleep, Time:632, State:, Info:  
> data: ID:172, User:root, Host:localhost, DB:, Cmd:Query, Time:0, State:starting, Info:show processlist

## 参考 ##

[https://blog.csdn.net/lanyang123456/article/details/79831537][Go _mysql]

[https://www.cnblogs.com/hanyouchun/p/6708037.html][https_www.cnblogs.com_hanyouchun_p_6708037.html]

[Go _mysql]: https://blog.csdn.net/lanyang123456/article/details/79831537
[https_www.cnblogs.com_hanyouchun_p_6708037.html]: https://www.cnblogs.com/hanyouchun/p/6708037.html