Sql server® 2012 t-sql fundamentals

Triggers

A trigger is a special kind of stored procedure—one that cannot be executed explicitly. Instead, it is 

attached to an event. Whenever the event takes place, the trigger fires and the trigger’s code runs. 

SQL Server supports the association of triggers with two kinds of events—data manipulation events 

(DML triggers) such as INSERT, and data definition events (DDL triggers) such as CREATE TABLE. 

You can use triggers for many purposes, including auditing, enforcing integrity rules that cannot 

be enforced with constraints, and enforcing policies. 

A trigger is considered part of the transaction that includes the event that caused the trigger to 

fire. Issuing a ROLLBACK TRAN command within the trigger’s code causes a rollback of all changes 

that took place in the trigger, and also of all changes that took place in the transaction associated 

with the trigger.

Triggers in SQL Server fire per statement and not per modified row.

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