create or replace TRIGGER Populate_specialite
AFTER UPDATE OR INSERT OR DELETE ON professeurs
FOR EACH ROW
DECLARE
succ VARCHAR2(15) := 'success' ;
BEGIN

IF inserting THEN
    UPDATE prof_specialite SET nb_professeurs = nb_professeurs + 1 WHERE specialite = :NEW.SPECIALITE;
    DBMS_OUTPUT.PUT_LINE( succ ) ;
END IF;
IF deleting THEN
    UPDATE prof_specialite SET nb_professeurs = nb_professeurs - 1 WHERE specialite = :OLD.SPECIALITE;
    DBMS_OUTPUT.PUT_LINE( succ ) ;
END IF;
IF updating THEN
    UPDATE prof_specialite SET nb_professeurs = nb_professeurs + 1 WHERE specialite = :NEW.SPECIALITE;
    UPDATE prof_specialite SET nb_professeurs = nb_professeurs - 1 WHERE specialite = :OLD.SPECIALITE;
    DBMS_OUTPUT.PUT_LINE( succ ) ;
END IF;

END;