GATE CS 2016 Set 1 Q22 — Transactions and Concurrency Control

The ACID properties of database transactions are fundamental rules that guarantee database transactions are processed reliably. They stand for:

• A – Atomicity: Ensures that all operations within a transaction are completed successfully; if not, the transaction is aborted and rolled back, leaving the database unchanged ("all or nothing").
• C – Consistency: Ensures that a transaction brings the database from one valid state to another, maintaining all predefined rules and constraints.
• I – Isolation: Ensures that concurrent execution of transactions leaves the database in the same state as if the transactions were executed sequentially.
• D – Durability: Ensures that once a transaction has been committed, its effects will persist in non-volatile memory, even in the event of a system crash.

Deadlock-freedom is a desirable property of concurrency control mechanisms (such as lock-based protocols) to prevent transactions from waiting on each other indefinitely. However, it is not one of the core ACID properties.

Thus, Deadlock-freedom is NOT a part of the ACID properties.