Pretty printing and cursor behavior in MongoDB - Mini Project: Build & Apply

Pretty Printing and Cursor Behavior in MongoDB

📖 Scenario: You are managing a small library database using MongoDB. You want to list all books in a readable format and understand how to work with the cursor that MongoDB returns when you query the collection.

🎯 Goal: Learn how to pretty print query results in MongoDB shell and how to use the cursor to iterate over documents.

📋 What You'll Learn

Create a collection called books with specific documents

Use a variable to hold the cursor returned by a query

Use the pretty() method to display documents in a readable format

Use the cursor's hasNext() and next() methods to iterate documents

💡 Why This Matters

🌍 Real World

Managing and querying collections in MongoDB is common in web applications, content management, and data analysis.

💼 Career

Understanding cursor behavior and pretty printing helps developers and database administrators efficiently retrieve and display data.

1

Create the books collection with sample documents

Insert three documents into the books collection with these exact fields and values: { 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 specified documents into the books collection
// Your code here

Need a hint?

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

2

Assign the query result to a cursor variable

Create a variable called cursor and assign it the result of db.books.find() to get all documents from the books collection.

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 }
])

// Assign the result of db.books.find() to a variable named cursor
// Your code here

Need a hint?

Use var cursor = db.books.find() to store the cursor.

3

Use pretty() to display documents nicely

Call the pretty() method on the cursor variable to display all documents in a readable format.

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 }
])

var cursor = db.books.find()

// Use pretty() on cursor to display documents nicely
// Your code here

Need a hint?

Call pretty() on the cursor variable like cursor.pretty().

4

Iterate over the cursor using hasNext() and next()

Write a while loop that uses cursor.hasNext() to check if there are more documents, and inside the loop call cursor.next() to get each document.

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 }
])

var cursor = db.books.find()
cursor.pretty()

// Use a while loop with cursor.hasNext() and cursor.next() to iterate documents
// Your code here

Need a hint?

Use while (cursor.hasNext()) { cursor.next() } to loop through all documents.