Pagination pattern with skip and limit in MongoDB - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the skip() method do in MongoDB pagination?

The skip() method tells MongoDB to ignore a specified number of documents before returning the rest. It helps to jump over documents to start from a certain position in the list.

beginner

What is the purpose of the limit() method in MongoDB queries?

The limit() method restricts the number of documents returned by a query. It controls how many results you get back, useful for showing a fixed number of items per page.

intermediate

How do skip() and limit() work together for pagination?

You use skip(n) to jump over the first n documents, then limit(m) to get the next m documents. This combination lets you fetch a specific page of results.

intermediate

What is a potential downside of using skip() for large page numbers?

Using skip() with large numbers can be slow because MongoDB still has to scan and discard those skipped documents internally before returning results.

beginner

Write a MongoDB query to get page 3 of a collection with 10 items per page.

Use skip(20).limit(10) because page 3 means skipping 2 pages of 10 items each (2 * 10 = 20), then limiting to 10 items.

What does db.collection.find().skip(5).limit(10) do?

A Skips first 5 documents, then returns next 10 documents

B Returns first 5 documents, then skips next 10 documents

C Returns 15 documents starting from the beginning

D Skips 10 documents, then returns 5 documents

The query skips the first 5 documents and then returns the next 10 documents.

If you want to show 20 items per page, how many documents do you skip to get page 4?

A 20

B 40

C 80

D 60

Page 4 means skipping 3 full pages: 3 * 20 = 60 documents.

Which method limits the number of documents returned in MongoDB?

A limit()

B skip()

C sort()

D find()

limit() controls how many documents are returned.

Why might using skip() be slow for large values?

A Because it sorts documents first

B Because it scans and discards skipped documents internally

C Because it limits the number of documents

D Because it caches all documents

skip() must scan and discard skipped documents, which can be slow for large skips.

What is the correct order to paginate with skip and limit?

A limit() then skip()

B sort() then skip()

C skip() then limit()

D find() then limit()

You first skip documents, then limit how many to return.

Explain how to use skip and limit together to get a specific page of results in MongoDB.

Think about how you jump over pages and then take a slice.

What are some performance considerations when using skip for pagination in MongoDB?

Consider what happens behind the scenes when skipping many documents.