Question

    Which of the following is an essential feature of the ACID

    properties of a transaction in a database system?
    A Transactions are automatically rolled back if they fail. Correct Answer Incorrect Answer
    B Transactions are processed sequentially to ensure consistency Correct Answer Incorrect Answer
    C Transactions can only be executed by one user at a time. Correct Answer Incorrect Answer
    D Transactions are allowed to interfere with each other if they do not conflict Correct Answer Incorrect Answer
    E Transactions are atomic, meaning they are either fully completed or fully rolled back. Correct Answer Incorrect Answer

    Solution

    The ACID properties of a database transaction ensure reliable processing of transactions, even in the presence of power outages, crashes, or other failures. These properties are:

    • Atomicity : This ensures that a transaction is treated as a single "unit," which either completes entirely or has no effect at all (it is rolled back). This prevents partial updates that could lead to inconsistent database states.
    • Consistency : A transaction takes the database from one consistent state to another.
    • Isolation : Transactions are isolated from each other to prevent interference.
    • Durability : Once a transaction is committed, its effects are permanent, even in the case of a system crash.
    Thus, atomicity ensures that the transaction is "all or nothing" and prevents any intermediate state from being visible to other transactions. Why other options are incorrect:
    • A is incorrect because automatic rollback is part of atomicity , but it is not the defining feature.
    • B is incorrect because while transactions must be consistent, they do not need to be processed sequentially.
    • C is incorrect because transactions can be executed concurrently as long as they are isolated and do not conflict.
    • D is incorrect because transaction isolation is crucial for maintaining data integrity, and transactions should not interfere with each other unless they are properly synchronized.

    Practice Next
    More Basics of Computers Questions
    ask-question