{}
public class TypeCdatabase.TypeARepository.GetById(id); // The important point here is that I don't know if the object is of TypeB or TypeC第二个问题是,它使多态性变得毫无用处,因为客户机实际上需要关心“
.* from zp01 p2 join (SELECT TYPEC,count(TYPEC) as cnt_typec FROM planning_cuisson group by TYPEC HAVINGCOUNT(TYPEC) > 0) p1 where p2.type_cuisson=p1.typec order by cnt_typec asc ;Query query= em.createQuery("SELECT