find method basics in MongoDB - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the find() method do in MongoDB?

The find() method retrieves documents from a collection that match a query. If no query is given, it returns all documents.

beginner

How do you use find() to get all documents from a collection?

Use db.collection.find({}). The empty curly braces mean no filter, so all documents are returned.

intermediate

What type of value does find() return?

find() returns a cursor, which is like a pointer to the matching documents. You can iterate over it to access each document.

intermediate

How can you limit the number of documents returned by find()?

You can chain .limit(n) after find() to get only n documents, like db.collection.find({}).limit(5).

beginner

What does find({ age: { $gt: 25 } }) do?

It finds all documents where the age field is greater than 25. $gt means 'greater than'.

What does db.users.find({}) return?

A All documents in the users collection

B No documents

C Only documents with empty fields

D An error

An empty query {} means no filter, so all documents are returned.

Which method limits the number of documents returned by find()?

A skip()

B limit()

C sort()

D count()

limit() restricts the number of documents returned.

What type of object does find() return?

A Cursor

B Array

C String

D Number

find() returns a cursor to iterate over matching documents.

How do you find documents where score is greater than 80?

A find({ score: { $lt: 80 } })

B find({ score: 80 })

C find({ score: { $gt: 80 } })

D find({ score: { $eq: 80 } })

$gt means 'greater than', so this finds scores above 80.

What happens if you call find() without parentheses like db.collection.find?

A It returns an empty cursor

B It returns all documents

C It throws an error

D It returns the function itself, not the results

Without parentheses, you get the function reference, not the query results.

Explain how the find() method works in MongoDB and how you can use it to retrieve documents.

Think about how you ask for data from a collection.

Describe how to limit the number of documents returned by a find() query and why this might be useful.

Consider when you only want a few results, not everything.