如何在金字塔中建立一个登录系统，使用mysql作为数据库来存储电子邮件和密码？

const express = require('express');
const mysql = require('mysql');
const bodyParser = require('body-parser');

const app = express();
app.use(bodyParser.urlencoded({ extended: true }));

// 创建MySQL连接
const connection = mysql.createConnection({
  host: 'localhost',
  user: 'root',
  password: 'your_mysql_password',
  database: 'login_system'
});

// 连接到MySQL数据库
connection.connect((err) => {
  if (err) throw err;
  console.log('Connected to MySQL database');
});

// 处理用户登录请求
app.post('/login', (req, res) => {
  const email = req.body.email;
  const password = req.body.password;

  // 查询用户信息
  const query = `SELECT * FROM users WHERE email = '${email}' AND password = '${password}'`;
  connection.query(query, (err, results) => {
    if (err) throw err;

    if (results.length > 0) {
      res.send('Login successful');
    } else {
      res.send('Invalid email or password');
    }
  });
});

// 启动服务器
app.listen(3000, () => {
  console.log('Server is running on port 3000');
});