HQL query over sub-classes - nhibernate

Question

I have the following entities defined in my Entity Model:
public class MyContainer
{
public virtual ICollection<Base> Subs { get; set; }
}
public abstract class Base
{
public virtual Guid Id { get; set; }
}
public abstract class Sub1 : Base
{
public virtual int MyValue { get; set; }
}
public abstract class Sub2 : Base
{
public virtual int MyValue { get; set; }
}
and the following FluentNHibernate mappings for the above entities:
public sealed class BaseMap : ClassMap<Base>
{
public BaseMap()
{
Table("BaseTable");
Id(e => e.Id);
}
}
public sealed class Sub1Map : SubClassMap<Sub1>
{
public Sub1Map()
{
Table("Sub1Table");
KeyColumn("BaseId");
Map(e => e.Myvalue);
}
}
public sealed class Sub2Map : SubClassMap<Sub2>
{
public Sub2Map()
{
Table("Sub2Table");
KeyColumn("BaseId");
Map(e => e.Myvalue);
}
}
When I run the following HQL:
select sub
from MyContainer container
join fetch container.Subs sub
where sub.MyValue = :p1
the SQL generated only applies a constraint in the WHERE clause for one of the sub-classes, however, the generated JOINS are correct, i.e., the following skeletal SQL is generated:
SELECT ...
FROM BaseTable bt
INNER JOIN Sub1Table st1 ON ...
INNER JOIN Sub2Table st2 ON ...
WHERE st1.MyValue = #p1
where as I'm expecting an additional OR in the WHERE clause:
SELECT ...
FROM BaseTable bt
INNER JOIN Sub1Table st1 ON ...
INNER JOIN Sub2Table st2 ON ...
WHERE st1.MyValue = #p1
OR st2.MyValue = #p2
Is there something I'm missing, or is there a way to re-write the HQL so that I can reference each sub-class in the WHERE clause and apply the constraint directly (assuming that it would then generate the additional constraint in the generated SQL)?
I'm using NHibernate 3.0.0.

Answer 1

MyValue should be declared and mapped in Base. It is not possible to filter base class by properties that are defined in subclasses without casting to the particular class:
where (b.class = Sub1 and b.MyValue = :p1) or (b.class = Sub2 and b.MyValue = :p1)
EDIT:
Or in FNH1.2 union subclassing can be used:
public class BaseMap : ClassMap<Base>
{
public BaseMap()
{
UseUnionSubclassForInheritanceMapping();
Table("BaseTable");
Id(e => e.Id);
}
}