MongoDB for Beginners: Learn by Doing

MongoDB is one of the most popular NoSQL databases today, known for its speed, flexibility, and developer-friendly syntax. Whether you're a backend developer or just exploring NoSQL databases, this guide will walk you through MongoDB fundamentals with hands-on shell commands.

What is MongoDB?

MongoDB is a document-oriented, NoSQL database built for speed, scalability, and developer productivity. Here are its key characteristics:

• Document-Oriented: Stores data in JSON-like documents (BSON format)
• Object-Oriented: Works well with object-based applications; no ORM needed
• Non-Relational: No tables or rows — collections and documents instead
• Flexible Schema: Dynamic schema — perfect for unstructured or evolving data
• Highly Scalable: Built for horizontal scaling across servers
• JS-Based Queries: Use familiar JavaScript syntax for querying

MongoDB listens on port 27017 by default.

Installing MongoDB (Windows)

You can run MongoDB locally or inside Docker. For a local Windows setup:

1. Download the MongoDB installer (.msi), Zip Package, or Mongo Shell (mongosh) from the official site
2. Create the required directories:

   C:\data\db
   C:\data\log
   

3. Add the MongoDB bin folder to your system PATH environment variable

Running MongoDB

Step 1 — Start the server (keep this terminal open):

mongod

Step 2 — Open the shell in a new terminal:

mongosh

You're now connected and ready to interact with your data.

Collections and Documents

MongoDB uses different terminology compared to relational databases:

| MongoDB | Relational DB | |---------------|---------------| | Collection | Table | | Document | Row | | _id field | Primary Key |

Basic Commands

// Show all non-empty databases
show dbs

// Create or switch to a database
use book_db

// Create a collection
db.createCollection("book")

// View all collections
db.getCollectionNames()

Inserting Documents

// Insert with auto-generated _id
db.book.insert({
  title: "Angular Programming",
  author: "Harsh Kumar",
  price: 545.0
})

// Insert with a manual _id
db.book.insert({
  _id: 2,
  title: "Java Programming",
  author: "Gaurav Sharma",
  price: 745
})

// Insert with extra fields
db.book.insert({
  _id: 3,
  title: "MongoDB",
  price: 745,
  publishedYear: 2020
})

Querying Documents

// View all documents
db.book.find()

// Pretty-print results
db.book.find().pretty()

// Filter by a field value
db.book.find({ price: 750 })

// OR condition
db.book.find({ $or: [{ _id: 2 }, { title: "Java Programming" }] })

// Greater than ($gt)
db.book.find({ price: { $gt: 800 } }).pretty()

Updating Documents

// Update using $set
db.book.update(
  { title: "Python for Beginners" },
  { $set: { title: "Angular Programming", price: 650 } }
)

// Update a single field by _id
db.book.update({ _id: 3 }, { $set: { price: 650 } })

// Save — inserts if _id doesn't exist, updates if it does
db.book.save({
  _id: 100101,
  title: "Java Programming",
  price: 890
})

Deleting Documents

// Delete by _id
db.book.remove({ _id: 4 })

// Delete by field value
db.book.remove({ title: "React JS" })

Admin Commands

// Count documents in a collection
db.book.find().count()

// Drop a collection
db.book.drop()

// Drop the current database
db.dropDatabase()

Creating Users

use order_db

db.createUser({
  user: "ramanuj",
  pwd: "password",
  roles: [
    { role: "readWrite", db: "order_db" }
  ]
})

This grants ramanuj read/write access to order_db.

Summary

By the end of this guide you've covered:

• What MongoDB is and how it differs from traditional RDBMS
• How to install and run MongoDB locally
• Core concepts: databases, collections, documents, and _id
• Full CRUD operations using the MongoDB shell
• How to create users and manage database access

This is a solid starting point for developers moving from relational databases or exploring NoSQL for the first time.