问 Hibernate JPA递归查询

我有以下查询，我使用hibernate一个JPA提供程序：

entityManager().createQuery(
            "SELECT page FROM ProjectPage page"
             +" left join fetch page.categorySet as category"
             + " where page.id = :id " 
             + " and  category.parentCategory is null "
             + " and  (category.status is null or category.status != :status_val) "
            ,ProjectPage.class).setParameter("id", id).setParameter("status_val", Status.DELETED).getSingleResult();

以下分别是 ProjectPage 和 Category 的实体：

@Entity
@Table(name="project_page")
@Configurable
public class ProjectPage {
@OneToMany( mappedBy = "parentPage")
private Set<Category> categorySet = new HashSet<Category>();
@Configurable
@Table(name="category")
@Entity