plsqlTriggers


Introduction

Introduction:

Triggers are a useful concept in PL/SQL. A trigger is a special type of stored procedure which does not require to be explicitly called by the user. It is a group of instructions, which is automatically fired in response to a specific data modification action on a specific table or relation, or when certain specified conditions are satisfied. Triggers help maintain the integrity, and security of data. They make the job convenient by taking the required action automatically.

Syntax

  • CREATE [ OR REPLACE ] TRIGGER trigger_name
  • BEFORE UPDATE [or INSERT] [or DELETE]
  • ON table_name
  • [ FOR EACH ROW ]
  • DECLARE
  • -- variable declarations
  • BEGIN
  • -- trigger code
  • EXCEPTION
  • WHEN ...
  • -- exception handling
  • END;