Hibernate Criteria：如果其子项的任何子项都有特定属性，则查找实体 [英] Hibernate Criteria: find entity if any of its children's children have a specific property

问题描述

我需要编写一个Criteria（或hql）来通过其子实体的子项的属性来查找父实体。这是我的实体：

  //顶级父类
 public class A {
 private Long ID; 
 private String someProperty; 
私人B b; 
 //和其他一些属性... 
} 
 
 //二级父类:) 
 public class B {
 private Long id ; 
私人列表< C> CLIST; 
 //和其他一些属性... 
} 
 
公共类C {
私有长ID; 
私人B b; 
私人列表< D> DLIST; 
 //其他属性.. 
} 
 
公共类D {
私人长ID; 
私人C c; 
 private String importantAttribute; 
 //其他属性.. 
} 
  

问题如下。我想获取 A 记录列表，如果有任何D记录具有条件importantAttribute ==something，并且A具有条件someProperty ==somethingelse。

如何为此编写一个hibernate标准？所有我可以写到现在是以下内容：
$ b $ pre $ 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。 试试这个

  Criteria criteria = getSession（）。createCriteria（A.class，a）; 
 criteria.createAlias 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）; 
  

I need to write a Criteria(or hql) to find a parent entity by a property of a child of its children entities. Here is my entities:

// 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..
}

The question is the following. I want to get the list of A records if any of D records have the condition importantAttribute=="something" and if A have the condition someProperty=="somethingelse".

How can I write a hibernate criteria for this? All I could write until now is the following:

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"));

Then I gave up.

解决方案

Try this

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");

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