DDL triggers, like regular triggers, fire stored procedures in response to an event. However, unlike DML triggers, they do not fire in response to UPDATE, INSERT, or DELETE statements on a table or view. Instead, they fire in response to a variety of Data Definition Language (DDL) events. These events primarily correspond to Transact-SQL statements that start with the keywords CREATE, ALTER, and DROP. Certain system stored procedures that perform DDL-like operations can also fire DDL triggers.