Using MySQL database in the express framework of node

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Related introduction

Preface

as everyone knows , stay Web Server side development , A very important part of operating a database , Even when the front and back ends tease each other, when the back end says that the front end is a cutaway , The front-end will retort that the background development is a CRUD Child , and CRUD Is the corresponding database Additions and deletions operation , and Mysql Database is one of the most commonly used databases .

Introduce

Used to say Mysql Database is a relational database management system , Because of its small size 、 Fast 、 Low total cost of ownership , In especial Open source This characteristic , Generally, the development of small and medium-sized websites and large-scale websites all choose MySQL As website database .

install Mysql

To use Mysql Words , First, install in the local environment Mysql Software can only be used , Can be in Official website download address Find the corresponding download link to download the software .

After installing the software , Get into cmd Software input command mysql -V You can see the installed Mysql Software information ：

Then perform mysql -uroot -p After entering the password, you can see the entry Mysql Terminal management interface , Here's the picture ：

If the above operations can be performed correctly , It means that the installation is correct Mysql The software .

install Navicat

Operate in the terminal Mysql Sometimes it is inconvenient , So it's time to Navicat To support Mysql The visual operation interface . Once installed , You can connect to the local database through software , Here's the picture ：

Start using

First , By using express-generator Generator to create a controlled Express project , as follows ：

npx express-generator express-mysql

next , Installation operation is required Mysql Database dependency . stay Node Used to be used in mysql Rely on operational databases , Now there is an upgraded version mysql2 You can manipulate the database , The library has been optimized compared with the former , So here's the installation mysql2 rely on , Execute the following code ：

npm install --save mysql2

Install well mysql2 After dependence , Create a new one db.js file , This file is used to write operations mysql Configuration file for , The contents are as follows ：

const mysql = require('mysql2')

const connection = mysql.createConnection({
  host: 'localhost',
  port: 3306,
  user: 'root',
  password: 'password',
  database: 'demo'
})
connection.connect()

module.exports = connection

adopt mysql.createConnection You can set up a database connection , Then you can operate through the return object of this function mysql database , The meanings of the configured attributes are as follows ：

attribute	significance
host	Connected database hostname , String type
port	Connected database port number , value type
user	Connected database user name , String type
password	The password of the connected database , String type
database	Database name of the connection , String type

After the file configuration , Through the first Navicat Medium demo Database users Add a record to the table , Here's the picture ：

Then you can start to operate the database , In routing files users.js in , Try querying a record in the database , And return to the page to display , as follows ：

const express = require('express');
const router = express.Router();
const db = require('../utils/db')

/* GET users listing. */
router.get('/', function(req, res, next) {
  db.query('select * from users', (err, users) => {
    if (err) throw err
    res.json(users)
  })
});

module.exports = router;

adopt db.query Naming can be done in node In the implementation of mysql The addition, deletion, modification, and query of , Enter the corresponding... In the browser Api After that, you can see the following information ：