Node.js — MongoDB

Installation

npm install mongoose

Connection

const mongoose = require('mongoose');

mongoose.connect('mongodb://localhost/mydb')
    .then(() => console.log('Connected to MongoDB'))
    .catch(err => console.error('Connection error:', err));

Schema and Model

const userSchema = new mongoose.Schema({
    name: { type: String, required: true },
    email: { type: String, required: true, unique: true },
    age: { type: Number, min: 0 },
    createdAt: { type: Date, default: Date.now }
});

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

CRUD Operations

// Create
const user = await User.create({ name: 'John', email: 'john@example.com' });

// Read
const users = await User.find({ age: { $gte: 18 } });
const user = await User.findById(id);

// Update
await User.findByIdAndUpdate(id, { name: 'Jane' });

// Delete
await User.findByIdAndDelete(id);

Querying

// Find with conditions
const users = await User.find({ name: 'John', age: { $gt: 25 } });

// Sort and limit
const users = await User.find().sort({ name: 1 }).limit(10);

// Select specific fields
const users = await User.find().select('name email');

Mini Practice

1. Connect to MongoDB
2. Create a schema
3. Perform CRUD operations
4. Query with conditions

Up Next

Continue with PostgreSQL — PostgreSQL integration.