Microsoft® SQL Server 2008 R2 Unleashed

Transactions and Triggers

SQL Server 2008 provides two types of Data Manipulation Language (DML) triggers: AFTER and INSTEAD OF. INSTEAD OF triggers perform their actions before any modifications are made to the actual table the trigger is defined on.

Whenever a trigger is invoked, it is always invoked within another transaction, whether it’s a single-statement AutoCommit transaction or a user-defined multistatement transaction. This is true for both AFTER triggers and INSTEAD OF triggers. Even though an INSTEAD OF trigger fires before, or “instead of,” the data modification statement itself, if a transaction is not already active, an AutoCommit transaction is still automatically initiated as the data modification statement is invoked and prior ...