A trigger is a special type of stored procedure that automatically runs when an event occurs in the database server. DML triggers run when a user tries to modify data through a data manipulation language (DML) event. DML events are INSERT, UPDATE, or DELETE statements on a table or view.
Types of Triggers
Data Definition Language (DDL) triggers
Data Manipulation Language (DML) triggers
Logon triggers
DML
Instead of Trigger: An Instead of trigger is fired instead of the triggering action such as an insert, update, or delete
After Trigger: An After trigger executes following the triggering action, such as an insert, update or delete
DDL Trigger
This type of trigger is fired against DDL statements like Drop Table, Create Table or Alter Table. DDL Triggers are always After Triggers.
