mysql database using the connection nodeJS

1. Installation module mysql

npm install mysql

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2. Create a generic method

Promise callback function used here, if you do not you can not use

const mysql = require('mysql')	//引用mysql模块

//设置数据库基本信息
const pool = mysql.createPool({
    host:"localhost",	//IP
    user:"root",	//用户名
    password:"root",	//密码
    database:"heartsofiron"	//数据库名称
})

//创建通用方法,这里使用了Promise函数回调，如果不需要也可以不用的
const query = function(sql){
    return  new Promise(function(callback,errorback){
	    //连接数据库
        pool.getConnection(function(err,conn){	
            if(err){
            	//连接失败
                console.error(err)
            }else{
            	//连接成功
            	//连接成功之后执行sql语句,
            	//第一个参数sql就是语句,
            	//第二个参数是执行sql语句后的回调
                conn.query(sql,function(qerr,vals,fields){
                    conn.release()	//释放连接（关闭连接）
                    console.log(vals)
                    callback(vals)	//回调
                })
            }
        })
    })
}

module.exports = query	//输出

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3. Use the above generic function

query("select * from users").then(ret=>{
	//这里的ret就是查询后的结果
	console.log(ret)
})

Here shows only the easiest way, but has been able to meet the basic needs, but also to allow beginners to understand, so do not add a lot of extra plugin.