Which property of a transaction ensures its either complete execution or complete rollback to the original state?

The property of a transaction that ensures either the complete execution of all operations or a full rollback to the original state is called atomicity. It is one of the key characteristics of transactions, part of the ACID properties.

Atomicity guarantees that a transaction is perceived as a single unit: if any part of the operation cannot be completed, all changes made within the transaction are rolled back to prevent the system from being left in an inconsistent state.