Install PostgreSQL (pg) in Node.js - Quick Guide

The pg module is a popular PostgreSQL client for Node.js. It helps you connect and interact with PostgreSQL databases. This guide will show you how to install and use it.

Prerequisites

Before installing the pg module, ensure you have:

- Node.js installed on your system. Check with node -v.

- A PostgreSQL database running locally or remotely.

- Basic knowledge of JavaScript and Node.js.

 
node -v

v18.12.1

Install pg Module

Use npm to install the pg module. Run this command in your project folder:

 
npm install pg

This will add the module to your package.json file. For TypeScript projects, you may also need TypeScript.

Basic Usage

Here’s a simple example to connect to a PostgreSQL database:

 
const { Pool } = require('pg');

const pool = new Pool({
  user: 'your_username',
  host: 'localhost',
  database: 'your_database',
  password: 'your_password',
  port: 5432,
});

pool.query('SELECT NOW()', (err, res) => {
  if (err) {
    console.error(err);
    return;
  }
  console.log(res.rows[0]);
  pool.end();
});

{ now: 2023-10-05T12:34:56.789Z }

The Pool class manages multiple connections. Use pool.query to run SQL commands.

Using Environment Variables

Store database credentials securely using environment variables. Install dotenv for this.

 
require('dotenv').config();

const pool = new Pool({
  user: process.env.DB_USER,
  host: process.env.DB_HOST,
  database: process.env.DB_NAME,
  password: process.env.DB_PASSWORD,
  port: process.env.DB_PORT,
});

Error Handling

Always handle errors to avoid crashes. Use try-catch blocks or promises.

 
pool.query('SELECT * FROM users')
  .then(res => console.log(res.rows))
  .catch(err => console.error(err));

Conclusion

The pg module makes PostgreSQL easy to use in Node.js. Follow this guide to install and connect to your database. For more modules, check our guide on MySQL2.