15일차 # 10-3: Types of Triggers

  *┌ Application Trigger

   └ Database Trigger ┌ DML operations on Table                 ┬ data event

        ├ DML operations on View = INSTEAD OF trigger ┘

        └ DDL                 ─ system event

  * Database Trigger = System Trigger on┌ Database : for all users

                 └ Schema   : for the specific user

  * DML Triggers┌ Statement Trigger : only ONCE - fires once even if no rows are affected at all

└ Row Trigger : for EACH row - not executed if no rows are affected at all

- 트리거 생성시 FOR EACH ROW 절이 있으면 행 트리거, 없으면 문장 트리거

  * Events

    1) DML statements that modify data in a table (INSERT, UPDATE, or DELETE)

    2) DDL statements (CREATE, ALTER, or DROP)

    3) System events such as startup(STARTUP), shutdown(SHUTDOWN), DB_ROLE_CHANGE, and error  

        messages(SERVERERROR)                            

    4) User events such as logon(LOGON) and logoff(LOGOFF)