What is a Trigger?

What is a Trigger?

A trigger is a pl/sql block structure which is fired when a DML statements like Insert, Delete, Update is executed on a database table. A trigger is triggered automatically when an associated DML statement is executed.

Syntax of Triggers

The Syntax for creating a trigger is:

 CREATE [OR REPLACE ] TRIGGER trigger_name

 {BEFORE | AFTER | INSTEAD OF }

 {INSERT [OR] | UPDATE [OR] | DELETE}

 [OF col_name]

 ON table_name

 [REFERENCING OLD AS o NEW AS n]

 [FOR EACH ROW]

 WHEN (condition) 

 BEGIN

   --- sql statements 

 END;