Can you explain the principle of atomicity in the context of ACID transactions?

Atomicity is one of the ACID principles, guaranteeing that a transaction in a database is executed as a single unit: either all its operations complete successfully, or none of them are applied.

This means that if an error occurs during the transaction, all changes made within it are rolled back, and the database is restored to its original state. Thus, atomicity prevents partially completed operations that could lead to data inconsistency.

Example: when transferring money between accounts, the amount is first deducted from one account and then credited to another. If the second operation fails, the first is also canceled to prevent money from 'disappearing' or 'appearing' out of nowhere.