node.js数据库操作

node 中使用mysql
        const http = require('http');
        const mysql = require('mysql');
        const url = require('url');
        const fs = require('fs');

        //1.连接到数据库
        let db = mysql.createConnection({
            host:'localhost',
            user: 'root',
            password:'',
            database:''
        });

        //连接池【解决并发问题】
        /*let db = mysql.createPool({
            connerctionLimit: 10,//默认就是10
            host:'localhost',
            user: 'root',
            password:'',
            database:''
        });*/


        //查询
        db.query('SELECT * FORM user_Table',(err,data)=>{
            if(err){
                console.log('错了');
            }else{
                console.log(data);
            }
        });

        //2.配合http
        http.createServer((req,res)=>{
            const {pathname,query}  = url.parse(req.url,true);

            if(pathname === '/reg'){
                //参数是否正确
                let {username,password} = query;
                if(!username || !password) {
                    res.write('用户和密码不能为空');
                    res.end();
                }else if(username.length>32){
                    res.write('用户名不能大于32位');
                    res.end();
                }else if(password.length>32){
                    res.write('密码不能大于32位');
                    res.end();
                }else{
                    db.query(`SELECT ID FROM user_table  WHERE username='${username}'`,(err,data)=>{
                        if(err){
                            res.write('数据库有错');
                            res.end();
                        }else if(data.length>0){
                            res.write('用户名已存在')；
                            res.end();
                        }else{
                            db.query(`SELECT INFO user_table (username,password) VALUES('${username}','${password}')`,err=>{
                                if(err){
                                    res.write('数据库有错');
                                    res.end();
                                }else {
                                    res.write('注册成功')；
                                    res.end();
                                }
                            })
                        }
                    })
                }

                //检查用户名是否存在

            }else if(pathname === '/login'){
                
            }else{
                fs.readFile('www'+pathname,(err,buffer)=>{
                    if(err){
                        res.writeHeader(404);
                        res.write('no found');
                    }else{
                        res.write(buffer);
                    }
                    res.end();
                })
            }
        })


        3.异步模块（co-mysql）
        const co = require('co-mysql');
        let conn = mysql.createPool({
            host:'localhost',
            user: 'root',
            password:'',
            database:''
        });

        let db = co(conn);

        http.createServer(async (req,res)=>{
            const {pathname,query}  = url.parse(req.url,true);

            if(pathname === '/reg'){
                //参数是否正确
                let {username,password} = query;
                if(!username || !password) {
                    res.write('用户和密码不能为空');
                    res.end();
                }else if(username.length>32){
                    res.write('用户名不能大于32位');
                    res.end();
                }else if(password.length>32){
                    res.write('密码不能大于32位');
                    res.end();
                }else{
                    try{
                        let data = await  db.query(`SELECT ID FROM user_table  WHERE username='${username}'`);
                        if(data.length>0){
                            res.write('用户名已存在')；
                        }else{
                            await db.query(`SELECT INFO user_table (username,password) VALUES('${username}','${password}')`);
                            res.write('注册成功')；
                        }
                    }catch(err){
                        res.write('数据库有错');
                    }
                    res.end();
                }

                //检查用户名是否存在

            }else if(pathname === '/login'){
                
            }else{
                fs.readFile('www'+pathname,(err,buffer)=>{
                    if(err){
                        res.writeHeader(404);
                        res.write('no found');
                    }else{
                        res.write(buffer);
                    }
                    res.end();
                })
            }
        })