nHibernate标准，用于在集合中的子项具有特定值时选择父项 [英] nHibernate Criteria for selecting a parent if a child in a collection has a specific value

问题描述

如果我具有以下类结构，如果其中一个孩子的孩子有一个特定的名字，那么选择父母的NHibernate条件是什么?

If I have the following class structure what is the NHibernate criteria to select a parent if one of it's children has a specific name?

 public class Child
 {
     public int Id { get; set; }
     public int Name { get; set; }
 }

 public class Parent
 {
     public int Id { get; set; }
     public IList<Child> Children { get; set; }
 }

推荐答案

我只是为集合创建一个别名并添加限制.

I'd just create an alias to the collection and add restrictions.

var parentsWithKidName = session.CreateCriteria<Parent>()
    .CreateAlias("Children", "c", JoinType.InnerJoin)
    .Add(Restrictions.Eq("c.Name", childName))
    .SetResultTransformer(Transformers.DistinctRootEntity()) 
    .List<Parent>();

这将导致

select p.* 
from parent p 
inner join child c on /* however it's mapped? */
where c.Name = ?

不同的根实体转换器将处理结果集并删除重复的父代.他们仍然碰到了电线.

The distinct root entity transformer will process the result set and remove duplicated parents. They still come across the wire though.

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