Drop collection vs deleteMany in MongoDB - Quick Revision & Key Differences

Recall & Review

beginner

What does the drop() method do in MongoDB?

The drop() method removes the entire collection and all its data from the database permanently.

beginner

What is the purpose of deleteMany() in MongoDB?

deleteMany() deletes multiple documents inside a collection based on a filter but keeps the collection itself.

intermediate

Which operation is faster for removing all data: drop() or deleteMany({})?

drop() is faster because it removes the whole collection at once, while deleteMany({}) deletes documents individually.

intermediate

After using drop(), what happens if you try to insert a document into the dropped collection?

MongoDB will recreate the collection automatically when you insert a new document after dropping it.

beginner

Can deleteMany() be used to delete all documents in a collection?

Yes, by passing an empty filter {}, deleteMany() deletes all documents but keeps the collection.

What does db.collection.drop() do?

A Deletes multiple documents but keeps the collection

B Deletes the entire collection and its data

C Deletes one document from the collection

D Renames the collection

drop() removes the whole collection and all its documents.

Which method deletes documents but keeps the collection?

A deleteMany()

B deleteOne()

C removeCollection()

D drop()

deleteMany() deletes documents matching a filter but does not remove the collection.

How do you delete all documents in a collection without dropping it?

A db.collection.deleteMany({})

B db.collection.drop()

C db.collection.deleteOne({})

D db.collection.removeCollection()

Passing an empty filter {} to deleteMany() deletes all documents but keeps the collection.

What happens if you insert a document after dropping a collection?

A Database crashes

B Error: collection does not exist

C Document is lost

D MongoDB recreates the collection automatically

MongoDB automatically recreates the collection when a new document is inserted after dropping.

Which is generally faster to remove all data from a collection?

A deleteOne({})

B deleteMany({})

C drop()

D updateMany()

drop() is faster because it removes the entire collection at once.

Explain the difference between drop() and deleteMany() in MongoDB.

Think about what happens to the collection itself in each case.

When would you choose deleteMany({}) over drop()?

Consider cases where collection metadata matters.