I'm having some trouble constructing the correct Criteria to do a particular query - after an afternoon of consultation with Professor Google, I'm hoping that someone can point me in the right direction.

I have two entities of interest: OutputTsDef and NamedAttribute

What I'm trying to do is to find all OutputTsDef that have a particular NamedAttribute value.

I can write a detached Criteria to find all NamedAttributes that have a given name and value:

       var attributesCriteria
           = DetachedCriteria.For<INamedAttribute>()
               .Add(Expression.Eq("Name", "some name"))
               .Add(Expression.Eq("Value", "some value"));

How do I inject this in to a query for OutputTsDef to restrict the results?

       var criteria
           = nHibernateSession.CreateCriteria(typeof(IOutputTsDefEntity));
       // What do I write here?
       var results = criteria.List();

NamedAttribute looks like this - note the use of [Any] as we can have NamedAttributes on many kinds of entity.

[AttributeIdentifier("DbKey", Name = "Id.Column", Value = "NamedAttributeID")]
[Class(Table = "NamedAttributes")]
public class NamedAttribute : BusinessEntity, INamedAttribute
{
    [Any(0, Name = "Entity", MetaType = "System.String", IdType = "System.Int32")]
    [MetaValue(1, Class = "Sample.OutputTsDef, Sample.Entities", Value = "OTD")]
    [MetaValue(2, Class = "Sample.OutputTimeSeriesAttributesEntity, Sample.Entities", Value = "OTA")]
    [Column(3, Name = "OwnerType")]
    [Column(4, Name = "OwnerKey")]
    public virtual IBusinessEntity Entity { get; set; }

   [Property(Column = "Name")]
   public virtual string Name { get; set; }

   [Property(Column = "Value")]
   public virtual string Value { get; set; }

   ... omitted ...

}

In regular SQL, I'd just include an extra "where" clause like this:

where OutputTsDefId
      in ( select distinct OwnerKey
           from NamedAttributes
           where Name = ?
             and Value = ?
             and OwnerType = 'OTD' )

What am I missing?

(Question also posted to the NHUsers mailing list - I'll copy any useful information from there, here.)