December 2002
Intermediate to advanced
928 pages
85h 29m
English
A trigger is a program that executes in response to a change in table data or to certain events that occur in the database. There is a predefined set of events that can be “hooked” with a trigger, enabling you to integrate your own processing with that of the database. A triggering event fires, or executes, the trigger.
Triggers are enabled on creation (via a CREATE TRIGGER statement) and can be disabled (so they do not fire) via an ALTER TRIGGER or ALTER TABLE statement:
ALTER TRIGGER trigger_name {ENABLE | DISABLE};
ALTER TABLE table_name {ENABLE | DISABLE} ALL
TRIGGERS;Triggers cannot be created on SYS-owned objects.