MongoDB MongoDB CRUD Operations

Question 1

Which method is used to insert a single document into a MongoDB collection?

Accepted Answer

insertOne()

Answer

insertOne() inserts a single document into a collection and returns an acknowledgment with the inserted document's _id.

Question 2

What does the findOne() method return when no matching document is found?

Accepted Answer

null

Answer

findOne() returns null when no document matches the specified query filter.

Question 3

Which update operator sets the value of a field in a document?

Accepted Answer

$set

Answer

$set assigns a new value to the specified field, creating it if it does not already exist.

Question 4

What option must be passed to updateOne() to create a new document if no match is found?

Accepted Answer

{ upsert: true }

Answer

Setting upsert: true causes MongoDB to insert a new document when no document matches the filter criteria.

Question 5

Which method removes a single document that matches the filter from a collection?

Accepted Answer

deleteOne()

Answer

deleteOne() deletes the first document that matches the filter, returning the count of deleted documents.

MongoDB Practice Test