Microsoft SQL Server 2012 Bible

Summary

DDL triggers provide a safety net — a way to track every change to the schema. The event model that can be tracked is comprehensive, and the data available to the trigger using the EventData() function and XML is dynamic and complete. Because DDL triggers can fire for such a broad range of events, the EventData() function returns XML data about the event.

DDL triggers are well suited to the following scenarios:

• Server-level DDL triggers can trap any event and are seen in Object Explorer under the Server Objects → Triggers node.
• Database-level DDL triggers exist in the user database, can only fire for database-level events, and are listed in Object Explorer in the [Database] → Programmability → Database Triggers node.
• DDL Triggers can fire for any specific DDL event, or for DDL Event Groups — a hierarchy of DDL events.

Triggers are a key feature of client/server databases. It is the trigger that enables the developer to create complex custom business rules that are strongly enforced at the Database Engine level. SQL Server has two types of triggers: INSTEAD OF triggers and AFTER triggers.

• Triggers enable the developer to create complex custom business rules that are strongly enforced at the Database Engine level. SQL Server has two types of DML triggers: INSTEAD OF triggers and AFTER triggers.
• INSTEAD OF triggers cancel the firing DML statement and do something else instead of the original DML statement.
• Triggers extend the lock duration, so try to place the code in the ...