A trigger is a special type of stored procedure that fires (executes) in response to an event. We typically use triggers to maintain data integrity rules that are too complicated to implement through constraints and referential integrity. We also use triggers to:
Triggers cannot support parameters and should not return values or result sets.
Microsoft SQL Server 2014 has two basic trigger types: DML triggers and DDL triggers.
Note
You can write DDL and DML triggers as Transact-SQL or CLR triggers. In this topic, we will use Transact-SQL to write DDL and DML triggers. For more information about CLR triggers, see CLR triggers at http://msdn.microsoft.com/en-us/library/ms131093.aspx.