How do I connect a Node.js application to a database using Express?

How do I connect a Node.js application to a database using Express?

You can connect a Node.js application to a database using Express by using a database driver or an ORM like Sequelize.

What database should I use with Node.js?

Popular choices include MongoDB for NoSQL or PostgreSQL/MySQL for SQL databases, depending on your needs.

Can you show me a code example?

Sure! Here's a simple example using MongoDB with Mongoose:

const express = require('express');
const mongoose = require('mongoose');

const app = express();

mongoose.connect('mongodb://localhost:27017/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true });

app.get('/', (req, res) => {
  res.send('Connected to the database!');
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});

What if I want to use PostgreSQL instead?

You can use the pg package for PostgreSQL. Here's a basic example:

const express = require('express');
const { Client } = require('pg');

const app = express();
const client = new Client({
  connectionString: 'postgresql://user:password@localhost:5432/mydatabase'
});

client.connect();

app.get('/', (req, res) => {
  res.send('Connected to PostgreSQL database!');
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});