传智播客java学习 jpa进阶_ejb初步

我今天学习了徐老师讲的ejb3的知识，我做了简单的笔记：
       上午讲的是jpa的知识，下午讲的是EJB3的知识：
       JPQL语句：hibernate的HQL语句一样。
简单查询:
  Query query = em.createQuery("SELECT c from Customer c");
  return query.getResultList();
命名查询
  @Entity
  @NamedQuery(name = "findCustomerByName",
              query = "SELECT c from Customer c
                                WHERE c.name
                                LIKE :name ")
       分页:
  query = em.createNamedQuery("findCustomerByName");
  query.setParameter("name", "t,om");
  query.setMaxResults(10);
  query.setFirstResult(3);
  List customers = query.getResultList();
设置参数:
  SELECT o from Order i WHERE i.orderNo = ?1
  query.setParameter(1, 100.00);
  SELECT o from Order i WHERE o.price = :price
  query.setParameter("price", 100.00);
单个实体检索
  query.getSingleResult();
查询集合:
  WHERE c.orders IS EMPTY
  WHERE CONCAT(c.fname, c.lname) = 't,om'
  SELECT c.id, c.name from Customer c
多态查询
  SELECT c from Customer c WHERE c.name LIKE :name
分组
  SELECT o.customer, COUNT(o.id) from Order o
                                     GROUP BY o.customer
排序
  order by
子查询
  SELECT o from Order I WHERE o.customer