ITPEC IP April 2024 Question 29

The update is confirmed in the database, used when the transaction ends normally — that is commit.

A transaction is a group of updates that must all take effect or none of them, such as taking money from one account and adding it to another. Until the transaction ends, its changes are provisional. When every step has succeeded, commit makes them final and permanent; if something fails, rollback cancels them and returns the database to its state before the transaction began.

Answer (b)

Why not others:

• •(a) — describes an exclusive lock, which blocks other transactions from updating data one transaction is updating
• •(c) — describes rollback, the opposite of commit, used when the transaction fails
• •(d) — describes a join, which combines tables through the columns that relate them

Key rule: A transaction ends in exactly one of two ways: commit on success makes its updates permanent, rollback on failure undoes them all.

Databases · AI-written, may contain errors