Triggers in SQL SERVER and Types of Trigges in SQL SERVER

Triggers are special types of Stored Procedures that are defined to execute automatically in place of or after data modifications. They can be executed automatically on the INSERT, DELETE and UPDATE commands on a table.we can't explicitly execute triggers.
    There are two types of triggers
    1)After Trigger
    2)Instead of Trigger

refer types of triggers in detail
After Triggers in SQL SERVER 2005 and After Trigger Syntax
Instead Of Triggers in SQL SERVER 2005 and it's Syntax