String and number types in MongoDB - Mini Project: Build & Apply

Working with String and Number Types in MongoDB

📖 Scenario: You are managing a small bookstore's inventory database using MongoDB. Each book has a title, author, and price. You want to store this information correctly using string and number types.

🎯 Goal: Create a MongoDB collection document for a book with proper string and number types. Then add a discount rate as a number and calculate the discounted price.

📋 What You'll Learn

Create a document with fields title and author as strings

Add a price field as a number

Add a discountRate field as a number representing a percentage

Calculate the discountedPrice by applying the discount rate to the price

💡 Why This Matters

🌍 Real World

Managing product data in a database requires correct use of string and number types to store names, prices, and calculations like discounts.

💼 Career

Database developers and data engineers often work with documents that mix strings and numbers and must perform calculations and updates on stored data.

1

Create the initial book document

Create a MongoDB document called book with these exact fields and values: title set to "The Great Gatsby", author set to "F. Scott Fitzgerald", and price set to 20.99 (a number).

MongoDB

// Create the book document with title, author, and price
// Your code here

Need a hint?

Use curly braces to create an object. Strings go in quotes, numbers do not.

2

Add a discount rate

Add a new field discountRate to the book document and set it to 15 (a number representing 15%).

MongoDB

const book = {
  title: "The Great Gatsby",
  author: "F. Scott Fitzgerald",
  price: 20.99
};
// Add discountRate field to book
// Your code here

Need a hint?

Add the new field inside the object with a comma after the previous field.

3

Calculate the discounted price

Create a new variable called discountedPrice that calculates the price after applying the discount rate. Use the formula: price minus (price times discountRate divided by 100).

MongoDB

const book = {
  title: "The Great Gatsby",
  author: "F. Scott Fitzgerald",
  price: 20.99,
  discountRate: 15
};
// Calculate discountedPrice
// Your code here

Need a hint?

Use arithmetic operators and access the fields with dot notation.

4

Add discounted price to the book document

Add the discountedPrice field to the book document and set its value to the discountedPrice variable you calculated.

MongoDB

const book = {
  title: "The Great Gatsby",
  author: "F. Scott Fitzgerald",
  price: 20.99,
  discountRate: 15
};

const discountedPrice = book.price - (book.price * book.discountRate / 100);
// Add discountedPrice field to book
// Your code here

Need a hint?

Add the new field inside the object with a comma after the previous field.