Oracle SQL Developer

9Triggers: Usage InformationThis topic discusses the use of database triggers with Oracle Express. Triggers aredatabase objects that can be created with PL/SQL code. This topic includes thefollowing topics:■■Overview of TriggersDesigning Triggers9.1 Overview of TriggersA database trigger is a stored subprogram associated with a database table, view, orevent. The trigger can be called once, when some event occurs, or many times, once foreach row affected by an INSERT, UPDATE, or DELETE statement. The trigger can becalled after the event, to record it or take some follow-up action. Or, the trigger can becalled before the event to prevent erroneous operations or fix new data so that itconforms to business rules. The executable part of a trigger can contain proceduralstatements as well as SQL data manipulation statements.Triggers are created using the SQL CREATE TRIGGER statement. The CREATE (orCREATE OR REPLACE) statement fails if any errors exist in the PL/SQL block.■■■■■■■■See Also:■■■Oracle Database Concepts for information on triggers.Oracle Database Application Developer's Guide - Fundamentals forinformation on triggers.Oracle Database SQL Reference for information on the CREATETRIGGER SQL statement.Types of TriggersNaming TriggersWhen Is the Trigger Fired?Controlling When a Trigger Is FiredAccessing Column Values in Row TriggersDetecting the DML Operation That Fired a TriggerEnabled and Disabled Trigger ModesError Conditions and Exceptions in the Trigger BodySee Also: Oracle Database SQL Reference for information on triggercreation syntaxTriggers: Usage Information 9-1