$inc operator for incrementing in MongoDB - Mini Project: Build & Apply

$inc Operator for Incrementing in MongoDB

📖 Scenario: You are managing a small online bookstore's inventory stored in a MongoDB collection. Each book document has a title and a stock count. When new books arrive, you need to increase the stock count for the existing books.

🎯 Goal: Learn how to use the $inc operator in MongoDB to increment the stock count of books in the inventory.

📋 What You'll Learn

Create a collection called books with three book documents having exact titles and stock counts.

Define a variable incrementValue to specify how many books to add to the stock.

Write an update query using the $inc operator to increase the stock of a specific book.

Complete the update operation by specifying the correct filter and update objects.

💡 Why This Matters

🌍 Real World

Managing inventory counts in an online bookstore or any retail system where stock levels change frequently.

💼 Career

Understanding how to increment numeric fields in a database is essential for roles like database administrator, backend developer, and data engineer.

1

Create the books collection with initial data

Create a MongoDB collection called books and insert these exact documents: { title: 'Learn MongoDB', stock: 5 }, { title: 'JavaScript Basics', stock: 8 }, and { title: 'Python for Beginners', stock: 10 }.

MongoDB

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

Need a hint?

Use insertMany to add multiple documents to the books collection.

2

Define the increment value

Create a variable called incrementValue and set it to 3 to represent how many books to add to the stock.

MongoDB

db.books.insertMany([
  { title: 'Learn MongoDB', stock: 5 },
  { title: 'JavaScript Basics', stock: 8 },
  { title: 'Python for Beginners', stock: 10 }
])

// Define the increment value
// Your code here

Need a hint?

Use const to declare the variable incrementValue and assign it the number 3.

3

Write the update query using $inc

Write an update query that uses db.books.updateOne to increase the stock of the book with title 'Learn MongoDB' by the value of incrementValue using the $inc operator.

MongoDB

db.books.insertMany([
  { title: 'Learn MongoDB', stock: 5 },
  { title: 'JavaScript Basics', stock: 8 },
  { title: 'Python for Beginners', stock: 10 }
])

const incrementValue = 3;

// Update the stock of 'Learn MongoDB' using $inc
// Your code here

Need a hint?

Use updateOne with a filter for { title: 'Learn MongoDB' } and an update object using $inc to increase stock.

4

Complete the update operation

Ensure the update query correctly specifies the filter as { title: 'Learn MongoDB' } and the update document uses { $inc: { stock: incrementValue } } to increment the stock count.

MongoDB

db.books.insertMany([
  { title: 'Learn MongoDB', stock: 5 },
  { title: 'JavaScript Basics', stock: 8 },
  { title: 'Python for Beginners', stock: 10 }
])

const incrementValue = 3;

db.books.updateOne(
  { title: 'Learn MongoDB' },
  { $inc: { stock: incrementValue } }
);

// Finalize the update operation
// Your code here

Need a hint?

Make sure the update query is complete and correctly formatted.