React Node MySql

In this lesson we will learn how add, read, delete data from MySql database (phpmyadmin, MySql Workbench, etc) using React in Frontend and Node Js Server.

We will also learn how to use Axios, Express, CORS, mysql package, prepared statements and many more things in this project.

• Client

We are using Axios to send request to our server running on port 9000.

1. Create

Axios.post('http://localhost:9000/create_user', 
{
    username : username,
    password: encodedPassword
}).then(()=>{
    console.log("request Send!")
})

Axios.post(endpoint, data_object).then((err, success)=>{})

1. Read

Axios.get('http://localhost:9000/get_all_users')
.then((response)=>{
   setUsers(response.data)
})

Axios.get(endpoint).then(response=>{})

1. Delete

Axios.delete(`http://localhost:9000/delete_user/${id}`)
.then(()=>{
   console.log("User Deleted")
})

Axios.delete(endpoint+param).then((err, success)=>{})

• Server

// Import Express
const express =  require('express')

/* 
Cross-origin resource sharing - 
Cross-origin resource sharing is a mechanism that allows
restricted resources on a web page to be requested from
another domain outside the domain from which the first
resource was served.
*/
const cors = require('cors')

// Create express application
const app = express()

// Use CORS
app.use(cors())

// Recognise the incoming Request Object as a JSON Object
app.use(express.json())

// Import MySql
const mysql = require('mysql')

// Connect to MySql database
const db = mysql.createConnection({
    user: "root",
    host: "localhost",
    password: "",
    database: "react-mysql"
})

// Fire app at port 9000
app.listen(9000, ()=>{
    console.log("Server Started. Jai Shree Ram!")
    db.connect(function(err) {
        if (err) throw err;
        console.log("Connected!");
    });
})

// Insert into database
app.post('/create_user', (req,res)=>{
    const username = req.body.username
    const password = req.body.password

    db.query("INSERT INTO users (username, password) VALUES (?, ?)", [username, password], (err, result)=>{
        if(err){
            console.log(err);
        }else{
            console.log("value inserted!");
        }
    })
})

// Get from database
app.get('/get_all_users',(req,res)=>{
    db.query("SELECT * FROM users", (err,result)=>{
        if(err){
            console.log(err)
        }else{
            res.send(result)
        }
    })
})

// Delete from database
app.delete("/delete_user/:id",(req,res)=>{
    const id = req.params.id

    db.query("DELETE FROM users WHERE id = ?", id, (err,result)=>{
        if(err){
            console.log(err)
        }else{
            console.log("deleted")
        }
    })
})

1 . Insert

db.query("INSERT INTO table_name (col1, col2, col3, ...) VALUES (?, ?, ?, ...)", [val1, val2, val3, ...], (err, result)=>{})

Note - values are not directly passed but send separately in array for SQL injections prevention.

2 . Get

db.query("SELECT * FROM table_name", (err,result)=>{})

3 . Delete

db.query("DELETE FROM table_name WHERE id = ?", id, (err,result)=>{})

Note - when we have to pass one value we can send it directly instead of array into prepared statement.

GitHub Link - https://github.com/yashkumat/React-Node-MySql