Why advanced indexing matters in MongoDB - See It in Action

Why advanced indexing matters

📖 Scenario: You are managing a small online bookstore database using MongoDB. The store has many books, and customers often search by title and author. To make searches faster, you want to use indexing.

🎯 Goal: Build a MongoDB collection with book data, add an index on the title field, then add a compound index on author and year fields to speed up queries.

📋 What You'll Learn

Create a MongoDB collection called books with 3 book documents having title, author, and year fields

Create an index on the title field

Create a compound index on author and year fields

Verify the indexes exist in the collection

💡 Why This Matters

🌍 Real World

Online stores and libraries use indexes to quickly find books by title or author without scanning the entire database.

💼 Career

Database administrators and backend developers use indexing to optimize query speed and improve user experience.

1

Create the books collection with 3 book documents

Create a MongoDB collection called books and insert exactly these 3 documents: { title: "The Hobbit", author: "J.R.R. Tolkien", year: 1937 }, { title: "1984", author: "George Orwell", year: 1949 }, and { title: "To Kill a Mockingbird", author: "Harper Lee", year: 1960 }.

MongoDB

// Insert the 3 book documents into the books collection
// Your code here

Need a hint?

Use db.books.insertMany([...]) with the exact documents.

2

Create an index on the title field

Create an index on the title field of the books collection using db.books.createIndex.

MongoDB

db.books.insertMany([
  { title: "The Hobbit", author: "J.R.R. Tolkien", year: 1937 },
  { title: "1984", author: "George Orwell", year: 1949 },
  { title: "To Kill a Mockingbird", author: "Harper Lee", year: 1960 }
])
// Create an index on the title field
// Your code here

Need a hint?

Use db.books.createIndex({ title: 1 }) to create an ascending index on title.

3

Create a compound index on author and year

Create a compound index on the author and year fields of the books collection using db.books.createIndex.

MongoDB

db.books.insertMany([
  { title: "The Hobbit", author: "J.R.R. Tolkien", year: 1937 },
  { title: "1984", author: "George Orwell", year: 1949 },
  { title: "To Kill a Mockingbird", author: "Harper Lee", year: 1960 }
])
db.books.createIndex({ title: 1 })
// Create a compound index on author and year
// Your code here

Need a hint?

Use db.books.createIndex({ author: 1, year: 1 }) to create the compound index.

4

Verify the indexes exist in the books collection

Use db.books.getIndexes() to list all indexes on the books collection.

MongoDB

db.books.insertMany([
  { title: "The Hobbit", author: "J.R.R. Tolkien", year: 1937 },
  { title: "1984", author: "George Orwell", year: 1949 },
  { title: "To Kill a Mockingbird", author: "Harper Lee", year: 1960 }
])
db.books.createIndex({ title: 1 })
db.books.createIndex({ author: 1, year: 1 })
// List all indexes on the books collection
// Your code here

Need a hint?

Use db.books.getIndexes() to see all indexes.