用于选择具有空子集合的所有实体的 nHibernate 标准

Question

我很难编写条件来选择所有子集合或孙集合为空的实体。我可以将这些作为单独的条件来执行，但我无法将其组合成一个条件。

类结构:

public class Component
    {
        public IList<Version> Versions { get; set; }
    }

    public class Version
    {
        public IList<SubscribeEvent> SubscribedEvents { get; set; }
        public IList<PublishEvent> PublishedEvent { get; set; }
    }

这不起作用:

return session
                .CreateCriteria<Component>("c")
                .CreateCriteria("Versions", "v")
                .Add(Restrictions.Or(Restrictions.IsEmpty("c.Versions"), Restrictions.And(Restrictions.IsEmpty("v.PublishedEvents"),
                                                                                        Restrictions.IsEmpty("v.SubscribedEvents"))))
                .SetCacheable(true);

Answer 1

我设法找到了一个解决方案，不确定它是否是最好的(我应该购买 NH profiler)

return session
            .CreateCriteria<Component>("c")
            .CreateAlias("Versions", "v", JoinType.LeftOuterJoin)
            .Add(Restrictions.Or(Restrictions.IsEmpty("c.Versions"),
                                 Restrictions.And(Restrictions.IsEmpty("v.SubscribedEvents"),
                                                  Restrictions.IsEmpty("v.PublishedEvents"))))
            .SetCacheable(true);