Document databases normally has atomic updates of a document. This may contain many parts and would require transactions in a relational db. Meaning you kind of

Document databases normally has atomic updates of a document. This may contain many parts and would require transactions in a relational db. Meaning you kind of get some transactions automatically. Other things are not possible to make transactions around and then you must try to create the app to handle the problems. And some document databases can actually use transactions, like FoundationDb.