$ne for not equal in MongoDB - Mini Project: Build & Apply

$ne for not equal in MongoDB queries

📖 Scenario: You are managing a small online bookstore database. You want to find books that are not by a specific author.

🎯 Goal: Build a MongoDB query using the $ne operator to find all books where the author is not 'J.K. Rowling'.

📋 What You'll Learn

Create a collection called books with 4 documents containing title and author fields

Add a variable called excludedAuthor set to 'J.K. Rowling'

Write a MongoDB query using $ne to find books where author is not equal to excludedAuthor

Assign the query result to a variable called booksNotByExcludedAuthor

💡 Why This Matters

🌍 Real World

Filtering data to exclude certain values is common in databases, such as finding all customers except those from a specific city.

💼 Career

Understanding how to use <code>$ne</code> helps in writing precise database queries, a key skill for backend developers and data analysts.

1

Create the books collection with sample data

Create a variable called books and assign it an array of 4 documents with these exact entries: { title: 'Harry Potter', author: 'J.K. Rowling' }, { title: 'The Hobbit', author: 'J.R.R. Tolkien' }, { title: '1984', author: 'George Orwell' }, and { title: 'The Catcher in the Rye', author: 'J.D. Salinger' }.

MongoDB

const books = [
  // Your code here
];

Need a hint?

Use an array with 4 objects, each having title and author keys.

2

Set the excludedAuthor variable

Create a variable called excludedAuthor and set it to the string 'J.K. Rowling'.

MongoDB

const books = [
  { title: 'Harry Potter', author: 'J.K. Rowling' },
  { title: 'The Hobbit', author: 'J.R.R. Tolkien' },
  { title: '1984', author: 'George Orwell' },
  { title: 'The Catcher in the Rye', author: 'J.D. Salinger' }
];

// Your code here

Need a hint?

Use const excludedAuthor = 'J.K. Rowling';

3

Write the MongoDB query using $ne

Create a variable called query and assign it an object that uses $ne to find documents where author is not equal to excludedAuthor. The query should look like { author: { $ne: excludedAuthor } }.

MongoDB

const books = [
  { title: 'Harry Potter', author: 'J.K. Rowling' },
  { title: 'The Hobbit', author: 'J.R.R. Tolkien' },
  { title: '1984', author: 'George Orwell' },
  { title: 'The Catcher in the Rye', author: 'J.D. Salinger' }
];

const excludedAuthor = 'J.K. Rowling';

// Your code here

Need a hint?

Use { author: { $ne: excludedAuthor } } as the query object.

4

Find books not by the excluded author

Create a variable called booksNotByExcludedAuthor and assign it the result of filtering books using the query with $ne. Use books.filter(book => book.author !== excludedAuthor).

MongoDB

const books = [
  { title: 'Harry Potter', author: 'J.K. Rowling' },
  { title: 'The Hobbit', author: 'J.R.R. Tolkien' },
  { title: '1984', author: 'George Orwell' },
  { title: 'The Catcher in the Rye', author: 'J.D. Salinger' }
];

const excludedAuthor = 'J.K. Rowling';

const query = { author: { $ne: excludedAuthor } };

// Your code here

Need a hint?

Use books.filter(book => book.author !== excludedAuthor) to get the filtered list.