MCQ IN COMPUTER SCIENCE & ENGINEERING

Detailed explanation-1: -The correct is option 4. Trigger is a statement that is executed automatically by the system as a side effect of modification to the database. Trigger has three parts: Trigger statement or event is the SQL statement that causes a trigger to be fired.

Detailed explanation-2: -A BEFORE triggered action executes before the triggering statement, that is, before the occurrence of the trigger event. An AFTER triggered action executes after the action of the triggering statement is complete. BEFORE and AFTER triggered actions execute even if the triggering statement does not process any rows.

Detailed explanation-3: -Trigger: A trigger is a stored procedure in database which automatically invokes whenever a special event in the database occurs. For example, a trigger can be invoked when a row is inserted into a specified table or when certain table columns are being updated.

Detailed explanation-4: -Triggers are database object. Basically, these are a special type of stored procedure that is automatically fired/executed when a DDL or DML command statement related to the trigger is executed. Triggers are used to assess/evaluate data before or after data modification using DDL and DML statements.