Databases with MongoDB

In This Section, You Will Learn:

• • Why databases are essential
• • SQL vs NoSQL databases
• • MongoDB – document-based database
• • Setting up MongoDB Atlas (cloud)
• • CRUD operations with Mongoose
• • Connecting your API to the database

Why You Need a Database

• Without a database, data disappears when the server restarts.
• Databases Store:
• • User accounts and profiles
• • Products and inventory
• • Orders and transactions
• • Messages and comments
• • Any data that needs to persist
• Two Main Types:
• • SQL (Relational): MySQL, PostgreSQL
• • NoSQL (Document): MongoDB
• We'll use MongoDB because:
• • Works naturally with JavaScript (JSON)
• • Flexible schema (no rigid structure)
• • Great for modern web applications

SQL vs NoSQL

• SQL (Structured Query Language):
• • Data in tables with rows and columns
• • Fixed schema (structure defined upfront)
• • Relationships between tables
• • Used by: Banks, traditional systems
• NoSQL (Not Only SQL):
• • Data as documents (like JSON objects)
• • Flexible schema (can change easily)
• • Great for rapid development
• • Used by: Startups, modern apps
• Example Document (MongoDB):
• “`
• {
• _id: ObjectId('…',
• name: 'Ahmed',
• email: 'ahmed@email.com',
• orders: [{ item: 'Laptop', price: 50000 }]
• }
• “`
• For beginners: Start with MongoDB, it's easier.

Setting Up MongoDB Atlas

• MongoDB Atlas is a free cloud database service.
• Setup Steps:
• 1. Create account at mongodb.com/atlas
• 2. Create a new cluster (free tier)
• 3. Create a database user (username/password)
• 4. Whitelist your IP address
• 5. Get your connection string
• Connection String:
• “`
• mongodb+srv://username:password@cluster.mongodb.net/database
• “`
• Store in .env File:
• “`
• MONGODB_URI=mongodb+srv://…
• “`
• Never commit passwords to GitHub!

Mongoose – ODM for MongoDB

• Mongoose makes working with MongoDB easier.
• Installing:
• “`
• npm install mongoose
• “`
• Connecting:
• “`
• const mongoose = require('mongoose');
• mongoose.connect(process.env.MONGODB_URI);
• “`
• Creating a Schema:
• “`
• const userSchema = new mongoose.Schema({
• name: { type: String, required: true },
• email: { type: String, unique: true },
• password: String,
• createdAt: { type: Date, default: Date.now }
• });
• const User = mongoose.model('User', userSchema);
• “`
• Schemas define the structure of documents.

CRUD Operations

• CRUD = Create, Read, Update, Delete
• Create:
• “`
• const newUser = new User({ name: 'Ahmed', email: 'a@b.com' });
• await newUser.save();
• // Or:
• await User.create({ name: 'Ahmed' });
• “`
• Read:
• “`
• const all = await User.find();
• const one = await User.findById(id);
• const filter = await User.find({ name: 'Ahmed' });
• “`
• Update:
• “`
• await User.findByIdAndUpdate(id, { name: 'New Name' });
• “`
• Delete:
• “`
• await User.findByIdAndDelete(id);
• “`
• These 4 operations cover 90% of database needs.