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Change Events

Change streams watch collections, databases, or deployments for changes.

When a change occurs on a watched resource, the change stream returns a change event notification document, with information on the operation and the changes it made.

Operation Types

Event Description
delete Occurs when a document is removed from the collection.
drop

Occurs when a collection is dropped from a database.

New in version 4.0.1.

dropDatabase

Occurs when a database is dropped.

New in version 4.0.1.

insert Occurs when an operation adds documents to a collection.
invalidate Occurs when an operation renders the change stream invalid.
rename

Occurs when a collection is renamed.

New in version 4.0.1.

replace Occurs when an update operation removes a document from a collection and replaces it with a new document.
update Occurs when an operation updates a document in a collection.

Resume Token

Each change event includes an _id field, which contain a document. This document can serve as the resume token when starting a change stream.