Node.js is known as an open-source runtime environment that is based on Google's V8 JavaScript engine. It can be used to create scalable and fast applications such as network applications, web servers, APIs, and microservices. Node.js provides asynchronous programming models and event-driven input/output operations, which helps in creating high-performance and efficient applications.
To create a web server using Node.js, you can follow these steps: Install Node.js on your computer. Open a command prompt and run the "npm init" command. This will generate the package.json file for your project. Install the Express.js library by running the command "npm install express". Copy the following code into a JavaScript file and run the file: const express = require('express') const app = express() const port = 3000 app.get('/', (req, res) => res.send('Hello World!')) app.listen(port, () => console.log(`Example app listening on port ${port}!`)) This code creates a web server and when you go to "http://localhost:3000" in your browser, "Hello World!" displays the text.
We can use "mysql" package to connect to MySQL database with Node.js. For this, first we need to install the mysql package using the 'npm i mysql' command. Afterwards, you can connect to the database as in the code block below and use SELECT, INSERT, UPDATE and DELETE queries. const mysql = require('mysql'); // Creating the database connection const con = mysql.createConnection({ host: "localhost", user: "username", password: "password", database: "database_name" }); // Connecting to the database con.connect(function(err) { if (err) throw err; console.log("Connected to database!"); // SELECT query con.query("SELECT * FROM tablo_adi", function (err, result, fields) { if (err) throw err; console.log(result); }); // INSERT query var sql = "INSERT INTO tablo_adi (colomn1, colomn2) VALUES ('val1', 'val2')"; con.query(sql, function (err, result) { if (err) throw err; console.log("1 record added"); }); // UPDATE query var sql = "UPDATE table_name SET colmn1 = 'val1' WHERE id = 2"; con.query(sql, function (err, result) { if (err) throw err; console.log(result.affectedRows + " record updated"); }); // DELETE query var sql = "DELETE FROM table_name WHERE id = 3"; con.query(sql, function (err, result) { if (err) throw err; console.log(result.affectedRows + " record deleted"); }); });