Connecting Node.js with MongoDB

MongoDB is a NoSQL, document-oriented database that stores data in JSON-like documents.
Connecting Node.js with MongoDB enables applications to handle flexible, scalable, and schema-less data.

1. Why Use MongoDB with Node.js?

• JSON-like data fits naturally with JavaScript

• Schema flexibility

• High scalability and performance

• Ideal for modern web and API-based applications

2. Required Package

Node.js connects to MongoDB using:

• mongodb (official driver)

• mongoose (ODM – Object Data Modeling)

Install MongoDB Driver

npm install mongodb

3. Connecting Using MongoDB Native Driver

3.1 Import MongoDB Client

const { MongoClient } = require('mongodb');

3.2 Create Connection URL

const url = 'mongodb://localhost:27017';
const client = new MongoClient(url);

3.3 Connect to Database

async function connectDB() {
  await client.connect();
  console.log('Connected to MongoDB');
  const db = client.db('testdb');
}
connectDB();

4. Performing Database Operations

4.1 Insert Data

const users = db.collection('users');

await users.insertOne({ name: 'Alice', age: 25 });

4.2 Read Data

const result = await users.find({ age: 25 }).toArray();
console.log(result);

4.3 Update Data

await users.updateOne(
  { name: 'Alice' },
  { $set: { age: 26 } }
);

4.4 Delete Data

await users.deleteOne({ name: 'Alice' });

5. Using MongoDB with Express.js

app.get('/users', async (req, res) => {
  const users = await db.collection('users').find().toArray();
  res.json(users);
});

6. Connecting Using Mongoose (Popular Approach)

Install Mongoose

npm install mongoose

Connect to MongoDB

const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost:27017/testdb')
  .then(() => console.log('MongoDB Connected'))
  .catch(err => console.error(err));

Define Schema and Model

const userSchema = new mongoose.Schema({
  name: String,
  age: Number
});

const User = mongoose.model('User', userSchema);

CRUD with Mongoose

const user = new User({ name: 'Bob', age: 30 });
await user.save();

7. MongoDB Native Driver vs Mongoose

8. Best Practices

• Use environment variables for DB URLs

• Handle connection errors properly

• Close connections when required

• Use indexes for performance

9. Typical Application Flow

Client Request
     ↓
Express Route
     ↓
MongoDB Query
     ↓
Database Response
     ↓
JSON Response

10. Summary

• MongoDB integrates smoothly with Node.js

• Supports flexible, document-based storage

• Can be used via native driver or Mongoose

• Common choice for REST APIs and scalable apps