Rows vs documents thinking in MongoDB - Hands-On Comparison

Understanding Rows vs Documents Thinking in MongoDB

📖 Scenario: You are working for a small bookstore that wants to store information about books and their authors. The bookstore is moving from a traditional table-based database to MongoDB, which uses documents instead of rows.Your task is to create a simple MongoDB collection that shows how data is stored as documents, not rows, and understand the difference in thinking.

🎯 Goal: Build a MongoDB collection named books with documents that include book titles, authors, and publication years. Learn how to think in documents instead of rows.

📋 What You'll Learn

Create a MongoDB collection named books.

Insert three book documents with fields: title, author, and year.

Add a configuration variable minYear to filter books published after a certain year.

Write a query to find all books published after minYear.

Add a final step to count how many books match the filter.

💡 Why This Matters

🌍 Real World

Many modern applications use MongoDB to store data as documents, which is more flexible than traditional rows. This project helps beginners understand this difference.

💼 Career

Understanding document-based databases like MongoDB is essential for roles in backend development, data engineering, and database administration.

1

Create the books collection with three book documents

Create a MongoDB collection called books and insert exactly these three 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 three book documents into the books collection
// Your code here

Need a hint?

Use db.books.insertMany() with an array of three objects.

2

Add a variable minYear to filter books published after a certain year

Create a variable called minYear and set it to 1940. This will be used to find books published after 1940.

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 minYear variable
// Your code here

Need a hint?

Use const minYear = 1940 to create the variable.

3

Write a query to find books published after minYear

Write a MongoDB query using db.books.find() to find all books where the year field is greater than minYear. Use the query { year: { $gt: minYear } }.

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 }
])

const minYear = 1940;

// Query books with year greater than minYear
// Your code here

Need a hint?

Use db.books.find({ year: { $gt: minYear } }) and assign it to booksAfterMinYear.

4

Count how many books match the filter

Add a line to count the number of books found by the query and store it in a variable called countBooks. Use booksAfterMinYear.count().

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 }
])

const minYear = 1940;

const booksAfterMinYear = db.books.find({ year: { $gt: minYear } });

// Count the number of books found
// Your code here

Need a hint?

Use booksAfterMinYear.count() to get the count.