tailieunhanh - Lecture Database - Chapter 9(2): Triggers-cursor

Trigger is like a procedure that is automatically invoked by the DBMS in response to specified changes to data base. Trigger is like a ‘Daemon that monitors a data base, and is executed when the data base is modified in a way that matches the event specification. | CHAPTER 9 tt TRIGGERS-CURSOR Trigger Trigger is like a procedure that is automatically invoked by the DBMS in response to specified changes to data base Trigger is like a Daemon that monitors a data base and is executed when the data base is modified in a way that matches the event specification A data base that has a set of associated triggers is called an active database Trigger Parts Event A change to data base that activates the trigger Restriction trigger restriction specifies a Boolean logical expression that must be TRUE for the trigger to fire Action 4 A procedure that is executed when the trigger is activated. Similar to stored procedures a trigger action can contain PL SQL .

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