├─index.js
├─db
| ├─db.js //封裝的操作函數(shù)
| ├─dbconfig.js //數(shù)據(jù)庫(kù)配置
| └sql.js  //sql語(yǔ)句

//單純的栗子
let user = {
  insert: "INSERT INTO user(id, name, age) VALUES(?,?,?)",
  update: "UPDATE user SET name=?, age=? WHERE id=?",
  delete: "DELETE FROM user WHERE id=?",
  queryById: "SELECT * FROM user WHERE id=?",
  queryAll: "SELECT * FROM user",
};
module.exports = {
  user,
};

let mysqlConfig = {
    host: "1.2.3.4",
    user: "******",
    password: "******",
    port: "******",
    database: "******",
  };
module.exports = mysqlConfig

const mysql = require("mysql");
const $dbConfig = require("./dbconfig.js"); //注意改成自己項(xiàng)目中的路徑
const sql = require("./sql.js"); 
const pool = mysql.createPool($dbConfig); // 使用連接池

let dbAdd = (table, req, res, next) => {
  return new Promise((resolve,reject)=>{
    pool.getConnection((err, connection) => {
      let paramValue = paramList(req);
      connection.query(sql[table].insert, [...paramValue], (err, result) => {
        if(err){
          reject(err)
        }
        resolve(result)
        connection.release();
      });
    });
  })
};

let dbDelete = (table, req, res, next) => {
  let paramValue = paramList(req);
  return new Promise((resolve,reject)=>{
    pool.getConnection((err, connection) => {
      connection.query(sql[table].delete, [...paramValue], (err, result) => {
        if(err){
          reject(err)
        }
        resolve(result)
        connection.release();
      });
    });
  })
};

let dbUpdate = (table, req, res, next) => {
  let paramValue = paramList(req);
  return new Promise((resolve,reject)=>{
    pool.getConnection((err, connection) => {
      connection.query(sql[table].update, [...paramValue], (err, result) => {
        if(err){
          reject(err)
        }
        resolve(result)
        connection.release();
      });
    });
  })
};

let dbQueryById = (table, req, res, next) => {
  let paramValue = paramList(req);
  return new Promise((resolve,reject)=>{
    pool.getConnection((err, connection) => {
      connection.query(sql[table].queryById, [...paramValue], (err, result) => {
        if(err){
          reject(err)
        }
        resolve(result)
        connection.release();
      });
    });
  })
};

let dbQueryAll = (table, req, res, next) => {
  return new Promise((resolve,reject)=>{
    pool.getConnection((err, connection) => {
      connection.query(sql[table].queryAll, (err, result) => {
        if(err){
          reject(err)
        }
        resolve(result)
        connection.release();
      });
    });
  })
};

let paramList = (obj) => {
  let paramArr = [];
  for (let key in obj) {
    if (obj[key]) {
      paramArr.push(obj[key]);
    }
  }
  return paramArr;
};

app.post("/login",async (req,res) =>{
  const {username,password} = req.body // 接收數(shù)據(jù)
    try {
       //看這里， 我們使用username的方式去數(shù)據(jù)庫(kù)進(jìn)行用戶查找
      const {data} = await db.dbQueryById("user",{"username":username},res)
      // 接下來(lái)自己想象吧
    } catch (err) {
      res.json({
        code: "500",
        msg: "用戶不存在"
      });
    }
})