Because a single document can contain related data that would otherwise be modelled across separate parent-child tables in a relational schema, MongoDB’s atomic single-document operations already provide transaction semantics that meet the data integrity needs of the majority of applications. One or more fields may be written in a single operation, including updates to multiple sub-documents and elements of an array. The guarantees provided by MongoDB ensure complete isolation as a document is updated; any errors cause the operation to roll back so that clients receive a consistent view of the document.

However, for situations that require atomicity of reads and writes to multiple documents (in a single or multiple collections), MongoDB supports multi-document transactions:

• In version 4.0, MongoDB supports multi-document transactions on replica sets.
• In version 4.2, MongoDB introduces distributed transactions, which adds support for multi-document transactions on sharded clusters and incorporates the existing support for multi-document transactions on replica sets.

For details regarding transactions in MongoDB, see the Transactions page.