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Node怎么操作Mysql？最细没有之一

2021-12-06 22:02:01 阅读：140 来源： 互联网

标签：Node 最细 res Mysql sql let mysql query app

1.2 操作流程

1.2.1 下载mysql模块

npm i mysql

1.2.2 在后端js文件中引入mysql

const mysql = require('mysql')

1.2.3 先创建mysql数据库的配置连接

let connectObj = mysql.createConnection({
				host:'主机名',
				user:'用户名',
				password:'密码'
				port:'端口号',
				database:'要操作哪个数据库'
			})

1.2.4 使用connectObj.connect()连接msyql数据库

connectObj.connect()方法来连接mysql数据库

1.2.5使用connectObj.query

使用query方法执行sql语句

connectObj.query(sqlStr,(err,results)=>{  })

服务端的代码如下：

const experss = require('express');
const path = require('path');
//第一步：引入mysql包：
const mysql = require('mysql');

const app = experss();

app.listen(3000, () => {
    console.log(`web服务器工作在3000端口`);
});


//设置ejs: 
app.set('view engine', 'ejs'); //设置模板引擎为ejs
app.set('views', path.join(__dirname, 'moban'));
app.engine('html', require('ejs').__express);

//第二步：创建mysql连接
const mysqlObj = mysql.createConnection({ host: '127.0.0.1', port: 3306, user: 'root', password: 'root', database: 'mydemo' });
//第三步：连接mysql数据库
mysqlObj.connect();

//显示查询界面：
app.get('/', (req, res) => {

    res.render('search.html');
});


//处理用户的查询：
app.get('/find', (req, res) => {
    let { xingming = '' } = req.query;
    if (xingming == '') {
        res.send(`<script>alert('查询关键词不能为空');location.href='/';</script>`);
        return;
    }

    let usr = '小李';
    let ages = 19;
    let emails = 'li@qq.com';

    // let sql = `select * from xsb where xm like '%${xingming}%'`;
    // let sql = `select * from xsb where xm like ?`;
    let sql = `insert into student(xingming,age,email)values(?,?,?)`;
    //mysqlObj.query(sql, (err, data) => {
    //  mysqlObj.query(sql, [`%${xingming}%`], (err, data) => {
    mysqlObj.query(sql, [usr, ages, emails], (err, data) => {
        // console.log(err, data);
        // res.send('OK');
        if (err) { //sql执行失败
            res.send(`sql执行失败`);
        } else { //sql执行成功
            res.render('userlist.html', { data });
        }

    });

});

search.html文件代码如下：

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <h2>查询学生</h2>
    <form action="/find" method="get">
        <div>
            <input type="text" name="xingming">&nbsp;
            <button>查询</button>
        </div>
    </form>
</body>

</html>

userlist.html文件代码如下：

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <table>
        <tr>
            <td>序号</td>
            <td>姓名</td>
            <td>性别</td>
            <td>所在系</td>
        </tr>
        <% for(let i = 0;i<data.length;i++){ %>
            <tr>
                <td>
                    <%=i %>
                </td>
                <td>
                    <%=data[i].xm %>
                </td>
                <td>
                    <%=data[i].sex %>
                </td>
                <td>
                    <%=data[i].szx %>
                </td>
            </tr>
            <% } %>

    </table>
</body>

</html>

标签：Node,最细,res,Mysql,sql,let,mysql,query,app
来源： https://blog.csdn.net/qq_64389035/article/details/121757140