1b
CREATE OR REPLACE TRIGGER TR1b AFTER DELETE ON Artiste FOR EACH ROW BEGIN UPDATE Album SET Artiste = NULL WHERE Artiste = :OLD.nom; END;
1c
CREATE OR REPLACE TRIGGER TR1c AFTER DELETE ON artiste FOR EACH ROW BEGIN DELETE album WHERE artiste = :OLD.nom; END; CREATE OR REPLACE TRIGGER T1c2 AFTER DELETE ON album FOR EACH ROW BEGIN DELETE chanson WHERE album = :OLD.titre; END;