ACID basics: Is a transaction the complete set of closely related update operations that must all succeed together or all fail together for the database to remain valid?

Difficulty: Easy

Correct Answer: Correct

Explanation:


Introduction / Context:
Transactions are the cornerstone of reliable database operations. The ACID properties (Atomicity, Consistency, Isolation, Durability) formalize expectations for correctness and recoverability. This question checks understanding of the “all-or-none” nature of transaction execution in relational systems.


Given Data / Assumptions:

  • The statement defines a transaction as a cohesive set of updates with all-or-none semantics.
  • We assume a conventional RDBMS supporting COMMIT and ROLLBACK.
  • We ignore advanced features such as savepoints or partial rollbacks for simplicity.


Concept / Approach:
Atomicity means that a transaction’s operations are indivisible: either every intended change is committed, or none are. Consistency ensures defined constraints hold before and after execution. Isolation keeps concurrent transactions from interfering in a way that violates serial equivalence. Durability guarantees that once committed, changes survive failures. The provided statement matches the atomicity perspective: all-or-none changes preserve validity when combined with appropriate constraints and business rules.


Step-by-Step Solution:

Group logically related changes into a single transaction boundary.Execute updates; if all succeed and constraints are satisfied, COMMIT persists them.If any step fails, ROLLBACK undoes all effects, maintaining database validity.Use isolation to avoid race conditions and dirty writes during concurrent access.


Verification / Alternative check:
Simulate a funds transfer: debit one account and credit another. If one update fails, rolling back both preserves consistency. Committing only one side would break invariants, illustrating why atomicity is essential.


Why Other Options Are Wrong:

  • Incorrect: Would negate ACID atomicity.
  • Distributed scope, autocommit, or isolation levels do not change the definition of a transaction’s all-or-none semantics.


Common Pitfalls:
Relying on autocommit for multi-step processes; forgetting to handle errors and thus leaving partial updates committed inadvertently.


Final Answer:
Correct

More Questions from Advanced SQL

Discussion & Comments

No comments yet. Be the first to comment!
Join Discussion