Atomicity is a desirable characteristic for database transactions. The name comes from the idea of an indivisible “atomic unit”, and it describes a method for processing transactions that treats each transaction as a single, indivisible unit (even if processing the transaction requires multiple steps). In other words, every step of the transaction must complete successfully or the entire transaction will fail and no change will be written to the database.
This is desirable because without atomicity, a transaction that’s interrupted while processing may only write a portion of the changes it’s supposed to make, which could leave the database in an inconsistent state.
It is one of the four ACID properties that are desirable for databases dealing with transactional workloads.