How to Connect to a MongoDB Database Using the Node.js Driver ?

Last Updated : 08 May, 2024

MongoDB is a popular, open-source, NoSQL (non-relational) database that provides high performance, high availability, and easy scalability. Unlike traditional relational databases, MongoDB stores a JSON-like format called BSON (Binary JSON).

In this article, we connect the MongoDB database to your backend application built by Node.js.

Setup for Database Connection

Installation : For connecting MongoDB to the backend, you have to install MongoDB on your local system or you can also create an account on MongoDB atlas and get your MongoDB credentials like URL.
Node.js Driver: The next step is to install the Node.js to your local system ( if it is not available)
Module: Installing the module ( MongoDB, Mongoose ) to connect the database.
Connect to MongoDB: This step establishes a connection to the MongoDB server.

Below mentioned are 2 approaches to connect database in the application.

Table of Content

Using MongoDB

Install MongoDB module. Establish a connection to the MongoDB database by creating an instance of the MongoClient class and providing the MongoDB connection URI.

Steps to Create Application

Step 1. Project Structure : Make a folder named 'mongodb-connection' and navigate to it using this command.

mkdir mongodb-connection  cd mongodb-connection

Step 2. Install Module : Install required module like mongodb , express.

npm i mongodb express dotenv

Updated dependencies in package.json file

"dependencies": {      "dotenv": "^16.4.5",      "express": "^4.19.2",      "mongodb": "^6.6.0"    }

Project Structure:

Example: This example demonstrates connection to database using the MongoDB.

JavaScript

// server.js   const { MongoClient } = require('mongodb');  // Connect to the MongoDB server async function connectToMongoDB() {     // Create a new MongoClient     const client = new MongoClient(process.env.DB_URI);     try {         await client.connect();         console.log('Connected to MongoDB');         return client.db();     } catch (error) {         console.error('Error connecting to MongoDB:', error);         throw error;     } }  module.exports = connectToMongoDB;

JavaScript

// app.js   const express = require('express') const app = express(); const dotenv = require('dotenv') const connectToMongoDB = require('./server')  dotenv.config()  const PORT = process.env.PORT || 5000  // Function to insert an item async function insertItem(itemData) {     try {         const db = await connectToMongoDB();         const collection = db.collection('items');         const result = await collection.insertOne(itemData);         console.log('Item inserted : ', result);         return result;     } catch (error) {         console.error('Error inserting item:', error);         throw error;     } }  // Example usage const newItemData = { name: 'Example Item',                        description: 'This is an example item',                        quantity: 3 }; insertItem(newItemData);  app.listen(PORT, () => {     console.log(`Server is running on PORT ${PORT}`) })

Output:

Using Mongoose

Installing Mongoose in your Node.js project using npm. Connect your MongoDB database by providing the MongoDB connection URI. Mongoose.connect method.

Steps to Create Application and Install Required Modules

Step 1. Project Structure : Make a folder named 'mongoose-connection' and navigate to it using this command.

mkdir mongoose-connection  cd mongoose-connection

Step 2. Install Module : Install required module like mongoose , express.

npm i mongoose express dotenv

Updated dependencies in package.json file

"dependencies": {      "express": "^4.19.2",      "mongoose": "^8.3.3",  }

Example: This example demonstrates connection to database using Mongoose.

JavaScript

// server.js  const mongoose = require('mongoose') const DB_URI = 'xxx-xxx'  const dbConnection = () => {     mongoose.connect(DB_URI);     console.log('Database is successfully connected!') }  // Define a schema const itemSchema = new mongoose.Schema({     name: String,     description: String,     quantity: Number });  // Define a model const Item = mongoose.model('Item', itemSchema)  module.exports = {     Item, dbConnection }

JavaScript

// app.js   const express = require('express'); const app = express(); const { Item, dbConnection } = require('./server')  const PORT = process.env.PORT || 8000; //  app.use(express.json()) dbConnection();   async function Inserting() {     // Example of creating a new document     const newItem = new Item({ name: 'Example Item',                               description: 'This is an example item',                               quantity: 3 });     await newItem.save()     console.log(newItem) }  Inserting(); app.listen(PORT, () => {     console.log(`Server is running on ${PORT}`) })