What is ACID in the context of relational databases? Decode it.

ACID is a set of properties that guarantee reliable transactions in relational databases:

• Atomicity — a transaction is either fully completed or not executed at all. If something goes wrong, all changes are rolled back.
• Consistency — after a transaction, the database remains in a correct state, satisfying all constraints and rules.
• Isolation — parallel transactions do not affect each other, as if they were executed sequentially.
• Durability — after a transaction is committed, its changes are saved in the database even in case of failures.

These properties ensure data integrity and correct operation with the data.