find method basics in MongoDB - Mini Project: Build & Apply

PMC: find method basics

📖 Scenario: You are managing a small library database. You want to find books by their titles and authors.

🎯 Goal: Build a MongoDB query using the find method to retrieve books from the collection.

📋 What You'll Learn

Create a collection named books with specific book documents

Add a filter variable to search for books by author

Use the find method with the filter to get matching books

Complete the query to return the results as an array

💡 Why This Matters

🌍 Real World

Finding specific records in a database is a common task in apps like libraries, stores, or user management systems.

💼 Career

Knowing how to use the find method in MongoDB is essential for backend developers and data engineers working with NoSQL databases.

1

Create the books collection with documents

Create a variable called books and assign it an array with these exact documents: { title: 'The Hobbit', author: 'J.R.R. Tolkien' }, { title: '1984', author: 'George Orwell' }, and { title: 'To Kill a Mockingbird', author: 'Harper Lee' }.

MongoDB

// Create the books array with the specified documents
// Your code here

Need a hint?

Use an array of objects with the exact titles and authors given.

2

Add a filter variable to find books by author

Create a variable called authorFilter and set it to an object that filters books where the author is exactly 'George Orwell'.

MongoDB

const books = [
  { title: 'The Hobbit', author: 'J.R.R. Tolkien' },
  { title: '1984', author: 'George Orwell' },
  { title: 'To Kill a Mockingbird', author: 'Harper Lee' }
];
// Create authorFilter to find books by George Orwell
// Your code here

Need a hint?

Use an object with the key author and value 'George Orwell'.

3

Use the find method with the filter

Create a variable called resultCursor and assign it the result of calling db.books.find(authorFilter).

MongoDB

const books = [
  { title: 'The Hobbit', author: 'J.R.R. Tolkien' },
  { title: '1984', author: 'George Orwell' },
  { title: 'To Kill a Mockingbird', author: 'Harper Lee' }
];

const authorFilter = { author: 'George Orwell' };
// Use find method on db.books with authorFilter
// Your code here

Need a hint?

Use db.books.find(authorFilter) exactly as shown.

4

Convert the cursor to an array to get the results

Create a variable called resultArray and assign it the result of calling resultCursor.toArray().

MongoDB

const books = [
  { title: 'The Hobbit', author: 'J.R.R. Tolkien' },
  { title: '1984', author: 'George Orwell' },
  { title: 'To Kill a Mockingbird', author: 'Harper Lee' }
];

const authorFilter = { author: 'George Orwell' };

const resultCursor = db.books.find(authorFilter);
// Convert resultCursor to an array
// Your code here

Need a hint?

Use resultCursor.toArray() to get the matching documents as an array.