To execute a user-named trigger, you must call the EXECUTE_TRIGGER built-in procedure, as shown here:
User-named PL/SQL subprograms can be written to perform almost any task for which one might use a user-named trigger.
As with all triggers, the scope of a user-named trigger is the definition level and below. When more than one user-named trigger has the same name, the trigger defined at the lowest level has precedence.
It is most practical to define user-named triggers at the form level.
Create a user-named trigger to execute user-named subprograms defined in a form document from menu PL/SQL commands and user-named subprograms. (User-named subprograms defined in a form cannot be called directly from menu PL/SQL, which is defined in a different document.) In the menu PL/SQL, call the EXECUTE_TRIGGER built-in to execute a user-named trigger, which in turn calls the usernamed subprogram defined in the current form.