Select the correct statement/s about a trigger. Marks: 2 MSQ a) The use of triggers should always ensure that the referential integrity is not violated. b) To design a trigger mechanism, we must specify conditions under which the trigger is to be executed and the actions to be taken when the trigger executes. c) Create table is a good example for valid triggering event. d) Triggers can also be activated before the event.
Answers
1. Triggers are devices that do not always maintain integrity. If we talk about unexpected triggering then the integrity is violated and we should not say that triggers always ensure referential integrity.
2. So, if we are talking about valid triggering then you must specify under which conditions the trigger has to be executed. The trigger does not execute its action in uncertainty. It should have proper mechanism and condition specified to occur.
3. To log the trigger, it is advisable to make a table but creating a table does not mean of valid triggering. The table can also be created for unexpected triggering.
4. A trigger executes automatically when a DDL or DML statement associated with it is executed. So, triggers can not be executed before an event.
Hence the correct option is (2).
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