What does "atomicity" mean in the context of CRUD?

Atomicity in the context of CRUD means that an operation either runs completely, or it doesn't run at all. A document can't be updated "halfway", either the whole operation succeeds, or the data stays in its original state.

#In simple terms, for a junior developer

• an operation is indivisible
• the database doesn't allow "half-saved" data
• if something goes wrong, MongoDB rolls the change back

#A way to think about it

If a document is being updated, it changes as a whole, and the application never sees it "in an intermediate state".

Summary: atomicity guarantees data integrity, every CRUD step either succeeds completely or is undone.