Can you explain the concept of D (Durability) in the ACID principle and its role in ensuring transaction reliability?

The D (Durability) concept in ACID means that after a transaction successfully completes, its changes are guaranteed to be saved in the system, even if a failure occurs, such as a power outage or server crash.

This is achieved through mechanisms like transaction log recording (logging), backups, and other state preservation methods. As a result, once a transaction is committed, its results will not be lost and will be available upon the next application startup.

Example: if you transfer money between accounts, after confirming the operation, the money will not disappear even in case of a sudden failure — the system will restore the state from the log.