Microsoft SQL Server 2012 Bible

Chapter 36

Creating Triggers

In This Chapter

Creating Instead of and After Triggers

Using the Transaction's Data Within the Trigger

Integrating Multiple Triggers

Creating DDL Database Triggers

Preventing Server or Database Changes

Reading Event Data with XML

Understanding Security Triggers

SQL Server triggers are special stored procedures attached to table events. They can't be executed directly, but fire only in response to an INSERT, UPDATE, or DELETE event on a table. Users can't bypass a trigger; and unless the trigger sends a message to the client, the end user is unaware of its actions.

Developing well-behaved triggers involves understanding transaction flow, locking, T-SQL, and stored procedures. Triggers have a few unique elements that require careful planning, but they provide execution of complex business rules and data validation.