Pagination pattern with skip and limit in MongoDB - Mini Project: Build & Apply

Pagination pattern with skip and limit

📖 Scenario: You are building a simple blog website. You have a collection called posts in your MongoDB database. Each post has a title and content. You want to show posts page by page, so users can see a few posts at a time instead of all at once.

🎯 Goal: Build a MongoDB query that uses skip and limit to get posts for a specific page number. This will help you show only a few posts per page.

📋 What You'll Learn

Create a variable called posts that contains 10 documents with title and content fields exactly as specified.

Create a variable called pageSize and set it to 3.

Create a variable called pageNumber and set it to 2.

Write a MongoDB query called pagedPosts that uses skip and limit to get the correct posts for the given pageNumber and pageSize.

💡 Why This Matters

🌍 Real World

Pagination is used in websites and apps to show data in small parts, like pages of posts or products, so users can browse easily without waiting for all data to load.

💼 Career

Knowing how to use skip and limit in MongoDB is important for backend developers and database administrators to efficiently manage large datasets and improve application performance.

1

DATA SETUP: Create the posts collection with 10 documents

Create a variable called posts that is an array of 10 objects. Each object must have a title and content field. Use these exact titles and contents: { title: 'Post 1', content: 'Content 1' }, { title: 'Post 2', content: 'Content 2' }, ..., up to { title: 'Post 10', content: 'Content 10' }.

MongoDB

# Your code here

Need a hint?

Use a list with 10 objects. Each object has title and content keys with string values.

2

CONFIGURATION: Set the page size

Create a variable called pageSize and set it to 3. This will control how many posts show on each page.

MongoDB

posts = [
    { 'title': 'Post 1', 'content': 'Content 1' },
    { 'title': 'Post 2', 'content': 'Content 2' },
    { 'title': 'Post 3', 'content': 'Content 3' },
    { 'title': 'Post 4', 'content': 'Content 4' },
    { 'title': 'Post 5', 'content': 'Content 5' },
    { 'title': 'Post 6', 'content': 'Content 6' },
    { 'title': 'Post 7', 'content': 'Content 7' },
    { 'title': 'Post 8', 'content': 'Content 8' },
    { 'title': 'Post 9', 'content': 'Content 9' },
    { 'title': 'Post 10', 'content': 'Content 10' }
]
# Your code here

Need a hint?

Just create a variable pageSize and assign the number 3.

3

CORE LOGIC: Set the page number

Create a variable called pageNumber and set it to 2. This means you want to get the second page of posts.

MongoDB

posts = [
    { 'title': 'Post 1', 'content': 'Content 1' },
    { 'title': 'Post 2', 'content': 'Content 2' },
    { 'title': 'Post 3', 'content': 'Content 3' },
    { 'title': 'Post 4', 'content': 'Content 4' },
    { 'title': 'Post 5', 'content': 'Content 5' },
    { 'title': 'Post 6', 'content': 'Content 6' },
    { 'title': 'Post 7', 'content': 'Content 7' },
    { 'title': 'Post 8', 'content': 'Content 8' },
    { 'title': 'Post 9', 'content': 'Content 9' },
    { 'title': 'Post 10', 'content': 'Content 10' }
]
pageSize = 3
# Your code here

Need a hint?

Just create a variable pageNumber and assign the number 2.

4

COMPLETION: Write the MongoDB query using skip and limit

Create a variable called pagedPosts that uses the MongoDB find() method on posts and applies skip and limit to get the posts for the current pageNumber and pageSize. Use skip = (pageNumber - 1) * pageSize and limit = pageSize.

MongoDB

posts = [
    { 'title': 'Post 1', 'content': 'Content 1' },
    { 'title': 'Post 2', 'content': 'Content 2' },
    { 'title': 'Post 3', 'content': 'Content 3' },
    { 'title': 'Post 4', 'content': 'Content 4' },
    { 'title': 'Post 5', 'content': 'Content 5' },
    { 'title': 'Post 6', 'content': 'Content 6' },
    { 'title': 'Post 7', 'content': 'Content 7' },
    { 'title': 'Post 8', 'content': 'Content 8' },
    { 'title': 'Post 9', 'content': 'Content 9' },
    { 'title': 'Post 10', 'content': 'Content 10' }
]
pageSize = 3
pageNumber = 2
# Your code here

Need a hint?

Use db.posts.find().skip((pageNumber - 1) * pageSize).limit(pageSize) to get the correct page.