Help putting together ICriteria plz

mreiland2009 · **Joined:** Thu Feb 26, 2009 4:36 pm **Posts:** 6

NHibernate 1.2
SQL Server 2005
.Net 3.5

I'm trying to find all entities that contain a child entity with a specific ID. The catch is that I want to load up the child entities in the same call.

My current solution.

Code:

return this.session.CreateCriteria(typeof(pARENT))
            .SetResultTransformer(new NHibernate.Transform.DistinctRootEntityResultTransformer())
            .CreateCriteria("children", NHibernate.SqlCommand.JoinType.LeftOuterJoin)
               .Add(Expression.IdEq(chID))
               .List<Parent>();

This returns all of the parents that have a child ID, but it's not loading up all of the children. Instead it's only loading up the child with the ID that we're searching with.

Any ideas on how to do this? In general whats the best way to find parent objects based upon the child objects ID's?

wolli · **Posted:** Tue Mar 10, 2009 6:21 am

Try and add

Code:

.SetFetchMode( "children", FetchMode.Join );

before you create the subcriteria. If that's still not working, use an alias:

Code:

this.session.CreateCriteria(typeof(pARENT),"p") 
            .SetFetchMode("p.children", FetchMode.Join)
            .SetResultTransformer(new NHibernate.Transform.DistinctRootEntityResultTransformer()) 
            .CreateCriteria("p.children" ) 
               .Add(Expression.IdEq(chID)) 
               .List<Parent>(); 

mreiland2009 · **Joined:** Thu Feb 26, 2009 4:36 pm **Posts:** 6

What I ended up doing to solve the problem is this:

Code:

return this.session.CreateCriteria(typeof(pARENT))
            .SetResultTransformer(new NHibernate.Transform.DistinctRootEntityResultTransformer())
            .CreateCriteria("children")
               .Add(Expression.IdEq(chID))
               .List<Parent>(); 

Note the lack of "NHibernate.SqlCommand.JoinType.LeftOuterJoin" in the CreateCriteria call.

My understanding is that normally you use this to pull in an entity and all of it's children in a single call. It has to be LeftOuterJoin otherwise entities with no children will not be included.

Why was this exhibiting the behavior I was witnessing before? A lot of times it seems like there's some magic that NHibernate is doing that I'm not aware of so I'd really like someone to explain this to me.