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9

Using Triggers

Triggers are procedures that are stored in the database and implicitly run, or fired, when something happens.

Traditionally, triggers supported the execution of a PL/SQL block when an INSERT, UPDATE, or DELETE occurred on a table or view. Starting with Oracle8i, triggers support system and other data events on DATABASE and SCHEMA. Oracle Database also supports the execution of a PL/SQL or Java procedure.

This chapter discusses DML triggers, INSTEAD OF triggers, and system triggers (triggers on DATABASE and SCHEMA). Topics include:

Designing Triggers

Creating Triggers

Coding the Trigger Body

Compiling Triggers

Modifying Triggers

Enabling and Disabling Triggers

Viewing Information About Triggers

Examples of Trigger Applications

Responding to System Events through Triggers

Using Triggers 9-1

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