Question

我需要编写一个Criteria（或hql）来通过子实体的子属性查找父实体。这是我的实体：

// The top level parent class
public class A {
    private Long id;
    private String someProperty;
    private B b;
    // and some other attributes...
}

// The second level parent class :)
public class B {
    private Long id;
    private List<C> cList;
    // and some other attributes...
}

public class C {
    private Long id;
    private B b;
    private List<D> dList;
    // Other attributes..
}

public class D {
    private Long id;
    private C c;
    private String importantAttribute;
    // Other attributes..
}

问题如下。如果任何D记录的条件为importantAttribute ==＆＃34;那么＆＃34;我希望获得A记录列表如果A有条件someProperty ==＆＃34; somethingelse＆＃34;。

如何为此编写休眠标准？我所能写的所有内容如下：

Criteria criteria = getSession().createCriteria(A.class, "a");
criteria.add(Restrictions.eq("a.someProperty", "somethingelse");

DetachedCriteria sub = DetachedCriteria.forClass(D.class, "d");
sub.add(Restrictions.eq("d.importantAttribute", "something"));
sub.setProjection(Projections.property("id"));

然后我放弃了。

Answer 1

试试这个

Criteria criteria = getSession().createCriteria(A.class, "a");
criteria.createAlias("a.b", "b");
criteria.createAlias("b.cList", "c");
criteria.createAlias("c.dList", "d");
criteria.add(Restrictions.eq("a.someProperty", "somethingelse");
criteria.add(Restrictions.eq("d.importantAttribute", "something");

Answer 2

如果使用HQL，这样的事情应该有效：

  TypedQuery<A> query = em
            .createQuery(
                    "SELECT a FROM D d join fetch d.c c join fetch c.b b join fetch b.a a where a.someProperty = :someProperty and d. importantAttribute = :importantAttribute",
                    A.class);
    query.setParameter("someProperty", "somethingelse");
    query.setParameter("importantAttribute", "something");
    List<A> results = query.getResultList();

您需要拥有＆＃34;私人A a;＆＃34; B类中定义的链接。

Hibernate Criteria：查找实体，如果其子女的子女有特定属性

2 个答案: