Question

召集所有NHibernate大师！

如果你们中的任何一个聪明人都能帮助我解决以下难题，我将非常感激：

我有一些实体描述来自各种来源的RSS源，这些源在一个名为FeedList的实体中组合在一起。

我试图仅选择与给定FeedList链接的不同SourceFeed实体。（即“WHERE FeedList.name ='feedlist1'”。

我一直在玩JoinQueryOver一段时间，但我似乎无法弄清楚如何获得所需的结果。

实体的相关性如下：

FeedList＆gt;饲料＆gt; FeedSource

因此FeedList包含许多Feed，每个Feed都属于FeedSource。

以下是实体的代码：

public class Feed
{
    public virtual int Id { get; set; }
    public virtual string Description { get; set; }
    public virtual FeedSource FeedSource { get; set; }
    public virtual string URL { get; set; }
}

public class FeedList
{
    public virtual int Id{get;set;}
    public virtual string Name { get; set; }
    public virtual IList<Feed> Feeds { get; set; }
}

public class FeedSource
{
    public virtual int Id { get; set; }
    public virtual string Name { get; set; }

}

我使用Fluent Automapping并使用以下覆盖：

public class FeedOverride : IAutoMappingOverride<Feed>
{
    public void Override(AutoMapping<Feed> mapping)
    {
        mapping.References<FeedSource>(map => map.FeedSource).Cascade.All();   

    }
}

public class FeedListOverride : IAutoMappingOverride<FeedList>
{
    public void Override(AutoMapping<FeedList> mapping)
    {
        mapping.HasManyToMany<Feed> (map => map.Feeds).Cascade.All().Table("FeedList_Feed");

    }
}

以下是一些创建一些示例数据的代码：

 private static void CreateSampleData()
    {
        using (var session = HibernateHelper.OpenSession())
        {
            using (var transaction = session.BeginTransaction())
            {
                //Create source 1 and feeds

                FeedSource source1 = new FeedSource() { Name = "BBC" };

                IList<Feed> feedsForSource1 = new List<Feed>(){ 
                                                                    CreateFeed("Sample Feed1",source1,"http://feed1.xml"),
                                                                    CreateFeed("Sample Feed2",source1,"http://feed2.xml")
                                                                };

                FeedList feedList1 = CreateFeedList("FeedList1", feedsForSource1);




                //Create source 2 and feeds

                FeedSource source2 = new FeedSource() { Name = "Sky" };

                IList<Feed> feedsForSource2 = new List<Feed>(){ 
                                                                    CreateFeed("Sample Feed3",source2,"http://feed3.xml"),
                                                                    CreateFeed("Sample Feed4",source2,"http://feed4.xml"),
                                                                    CreateFeed("Sample Feed5",source2,"http://feed5.xml")
                                                                };

                FeedList feedList2 = CreateFeedList("FeedList2", feedsForSource2);

                session.SaveOrUpdate(feedList1);
                session.SaveOrUpdate(feedList2);


                transaction.Commit();
            }
        }
    }

我想要实现的目标是什么？

如果我在SQL中描述它（非常糟糕），我希望做这样的事情：

select  distinct *
from FeedList as list
LEFT JOIN FeedList_Feed as list_feed
ON list.Id = list_feed.FeedList_id
LEFT JOIN Feed as feed
ON feed.FeedSource_id = list_feed.Feed_id
LEFT JOIN FeedSource as src
ON src.Id = list_feed.Feed_id
WHERE list.Name="a feedlist name"

非常感谢您的时间：）

Answer 1

好的，所以我终于成功地为所有感兴趣的人解决了这个问题：

<强>实体

public class Feed
{
    public virtual int Id { get; set; }
    public virtual string Description { get; set; }
    public virtual FeedSource FeedSource { get; set; }
    public virtual string URL { get; set; }
    public virtual FeedList FeedList { get; set; }
}

public class FeedList
{
    public virtual int Id{get;set;}
    public virtual string Name { get; set; }
    public virtual IList<Feed> Feeds { get; set; }
}

public class FeedSource
{
    public virtual int Id { get; set; }
    public virtual string Name { get; set; }
}

<强>覆盖

public class FeedOverride : IAutoMappingOverride<Feed>
{
    public void Override(AutoMapping<Feed> mapping)
    {
        mapping.References<FeedList>(map => map.FeedList).Cascade.All();
        mapping.References<FeedSource>(map => map.FeedSource).Cascade.All();
    }
}

public class FeedListOverride : IAutoMappingOverride<FeedList>
{
    public void Override(AutoMapping<FeedList> mapping)
    {
        mapping.HasManyToMany<Feed>(map => map.Feeds).Cascade.All().Table("FeedList_Feed");
        //mapping.HasMany<FeedListFeed>(map => map.Feeds).Cascade.All();
    }
}

最后：

查询

session.QueryOver<FeedList>()
                    .Inner.JoinAlias(f => f.Feeds, () => feedAlias)
                    .Where(fl => fl.Name == name)
                    .Select(x => feedAlias.FeedSource)
                    .List<FeedSource>().Distinct().ToList();

NHibernate JoinQueryOver

1 个答案: