Oracle PL/SQL in 10 Minutes, Sams Teach Yourself

Lesson 24. Using Triggers

In this lesson, you’ll learn what triggers are, why they are used, and how. You’ll also look at the syntax for creating and using them.

Understanding Triggers

Oracle statements are executed when needed, as are stored procedures. But what if you wanted a statement (or statements) to be executed automatically when events occur? For example:

Every time a customer is added to a database table, check that the phone number is formatted correctly and that the state abbreviation is in uppercase.

Every time a product is ordered, ...