C H A P T E R  5

Triggers

Triggers play an important role in any database developer's or database administrator's career. They provide the ability to execute code upon the occurrence of defined database, schema, or system events. Triggers can be useful for enhancing applications by providing database capabilities when a table event occurs, providing alerts on system event occurrences, and so much more. Triggers are an enormous topic because they are very intricate constructs. However, even though triggers can open up a world of possibilities, they are easy to use.

In this chapter, you will see recipes demonstrating the many different capabilities that triggers provide to you. If you are interested in learning how to create code that executes upon a database table–level event, then this is the chapter for you. If you want to learn how to create an intricate alerting system that will send e-mail and create logs upon system events, then look at the recipes in this chapter. Triggers are intricate building blocks that can provide an enormous benefit to our databases and applications as a whole. By learning how to incorporate these recipes into your applications, you will be able to solve many issues and enhance a number of your application features. Triggers can be one of the most useful tools to add to a DBA or application developer's arsenal.