Hibernate Criteria和多重连接 [英] Hibernate Criteria and multiple join

问题描述

 选择A.something，B.something，C.something，D. A.id = B.id_fk 
 JOIN C ON B.id = C.id_fk 
 JOIN D ON C.id = D.id_fk; 
  

解决方案

我有完全相同的问题，如下所示：

  return criteria.createCriteria（A.class）
 .createCriteria（b， join_between_a_b）
 .createCriteria（c，join_between_b_c）
 .createCriteria（d，join_between_c_d）
 .add（Restrictions.eq（some_field_of_D，someValue ））; 
  

注意：b，<$上面代码中的c $ c>c和d引用 A ， B 和 C 类，相应地（class A 具有属性 b 等等）。

对于这个解决方案，您甚至不需要 lazy 和 fetch 参数在中设置A.hbm.xml 。

is possible with Hibernate criteria do it?

select A.something, B.something, C.something, D.something
    from  A JOIN B on A.id = B.id_fk
          JOIN C ON B.id = C.id_fk
          JOIN D ON C.id = D.id_fk;

解决方案

I have got exactly the same problem, and was able to resolve it like this:

return criteria.createCriteria(A.class)
               .createCriteria("b", "join_between_a_b")
               .createCriteria("c", "join_between_b_c")
               .createCriteria("d", "join_between_c_d")
               .add(Restrictions.eq("some_field_of_D", someValue));

Note: "b", "c" and "d" in code above refer to attribute names in A, B and C classes, correspondingly (class A has attribute b and so on).

For this solution you don't even need to have lazy and fetch parameters to be set in your A.hbm.xml.

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