I'm stuck with a query I need to write.

Given the following model:

public class A : Entity<Guid>
{
    public virtual IDictionary<B, C> C { get; set; }
}

public class B : Entity<Guid>
{
}

public class C : Entity<Guid>
{
    public virtual int Data1 { get; set; }
    public virtual ICollection<D> D { get; set; }
}

public class D : Entity<Guid>
{
    public virtual int Data2 { get; set; }
}

I need to get a list of A instances that have a D containing some data for the specified B (parameter)

In the object model, that would be:

listOfA.Where(a => a.C[b].D.Any(d => d.Data2 == 0))

But I wasn't able to write a working HQL.

I'm able to write something like the following, which filters on C.Data1:

from A a
where a.C[:b].Data1 = 0

But I'm unable to do anything with the elements of a.C[:b].D (I get various parsing exceptions)

Here are the mappings, in case you're interested (nothing special, generated by ConfORM):

<class name="A">
  <id name="Id" type="Guid">
    <generator class="guid.comb" />
  </id>
  <map name="C">
    <key column="a_key" />
    <map-key-many-to-many class="B" />
    <one-to-many class="C" />
  </map>
</class>
<class name="B">
  <id name="Id" type="Guid">
    <generator class="guid.comb" />
  </id>
</class>
<class name="C">
  <id name="Id" type="Guid">
    <generator class="guid.comb" />
  </id>
  <property name="Data1" />
  <bag name="D">
    <key column="c_key" />
    <one-to-many class="D" />
  </bag>
</class>
<class name="D">
  <id name="Id" type="Guid">
    <generator class="guid.comb" />
  </id>
  <property name="Data2" />
</class>

Thanks!