Câu hỏi phỏng vấn MySQL
Câu hỏi

What happens to a trigger in MySQL if an operation which t...

Câu trả lời

In MySQL, the behavior of triggers in response to the failure of an operation they are associated with depends on the type of trigger and the point at which the failure occurs.

  • BEFORE Triggers: If a BEFORE trigger fails, the operation on the corresponding row is not performed. This means that if the operation that activates the BEFORE trigger (such as an insert, update, or delete) fails, the BEFORE trigger will not execute because it is activated by the attempt to insert or modify the row, regardless of whether the attempt subsequently succeeds[1].

  • AFTER Triggers: An AFTER trigger executes only if any BEFORE triggers and the row operation execute successfully. Therefore, if an error occurs during either a BEFORE trigger or the row operation itself, the AFTER trigger will not execute. This is because the AFTER trigger is contingent on the success of both the BEFORE triggers (if any) and the operation on the row[1][3].

Furthermore, for transactional tables, the failure of a statement that caused the trigger invocation should cause a rollback of all changes performed by the statement. This means that if a trigger (either BEFORE or AFTER) fails, t...

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