Oracle trigger if inserting or updating corso di restauro online dating
A trigger defined on a database fires for each event associated with all users.One use of triggers is to enforce business rules that apply to all client applications.In my experience, Developers/Business Analysts often tend to think in transaction workflows.
Unlike a subprogram, a trigger cannot be invoked directly.
Because the trigger executes whenever any client adds data to the table, no client can circumvent the rules, and the code that enforces the rules can be stored and maintained only in the trigger, rather than in every client application.
For other uses of triggers, see table (created in "Creating Tables").
NEXTVAL INTO : NEW.my_col3 FROM DUAL; END IF; IF : NEW.my_col4 IS NULL THEN (...) END IF; END IF; END; / -- Scenario 2 CREATE OR REPLACE TRIGGER my_trg1 BEFORE INSERT ON my_table FOR EACH ROW BEGIN IF : NEW.my_col3 IS NULL THEN SELECT my_seq.
NEXTVAL INTO : NEW.my_col3 FROM DUAL; END IF; IF : NEW.my_col4 IS NULL THEN (...) END IF; END; / CREATE OR REPLACE TRIGGER my_trg2 BEFORE UPDATE ON my_table FOR EACH ROW BEGIN IF : NEW.my_col IS NULL THEN raise_application_error(...); END IF; IF : NEW.my_col2 IS NULL THEN : NEW.my_col2 := (...); END IF; END; / I can't see any major advantage to one or the other.