ITPEC FE Subject A October 2024 Question 22
Which of the following is a property on a database that guarantees a result where a transaction either fully completes update processing or is revoked as if no processing took place at all?
Explanation
Atomicity — the all-or-nothing property of a transaction, one of the four ACID properties.
A transaction's updates are treated as one indivisible unit: either every update is committed, or, if anything fails, all of them are rolled back so the database looks as if the transaction never ran. That is exactly the guarantee the question describes.
Answer (a)
Why not others:
- •(b) Consistency — guarantees a transaction takes the database from one valid state to another, keeping integrity constraints; it says nothing about partial completion
- •(c) Durability — guarantees that once a transaction commits, its results survive later failures
- •(d) Isolation — guarantees that concurrent transactions do not see each other's intermediate results, as if they ran one after another
Key rule: ACID: Atomicity = all or nothing, Consistency = valid state to valid state, Isolation = no interference between concurrent transactions, Durability = committed results are permanent.
Databases · AI-written, may contain errors
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