insert into sites values(1, 'Chateau des Ducs', '12-FEB-2008', '21-FEB-2008', 70, 5);
insert into sites values(2, 'Chez Sto', '4-MAR-2008', '5-MAR-2008', 5, 21); /* viole la contrainte coh_notes */
insert into sites values(3, 'Cathedrale', '12-FEB-2008', '21-MAR-2008', 135, 7);