Hibernate version: 1.4

Assumption: a child object exists in one of the parent object's list of children

HQL:
from Parent p where (from Child c where c.Id = :childID) in p.Children

Parent Object Model:
public Guid Id
public String Name
public IList<Child> Children

Child Object Model:
public Guid Id
public String Name

This currently returns an exception:
unindexed collection before [] [from Parent p where (from Child c where c.Id = :childID) in p.Children]

Some direction on how to do this properly would be appreciated.

**I have researched the forums and the nHibernate Documentation. Please include some terminology or concept names that would help me understand more completely the nuisances of CreateQuery method.

Would something like following be helpful?

select c.Parent from Child c where ......

Thanks for the reply, however Child does not have a property: Parent.

I would like to keep it that way to avoid circular references.

Brian

Then what field / property marks the relation between parent and child?

Parent Object Model:
public Guid Id
public String Name
public IList<Child> Children

Yes but what determines on the child side as what parent a given child belongs to?

HQL: Query the objects not the DB.

<class name="Parent" table="Parents">
<bag name="Children" cascade="all-delete-orphan" lazy="true" table="ParentChildren">
<key column="idParent"/>
<many-to-many class="Child, [assembly]" column="idChild"/>
</bag>
</class>

Then, my friend as far as I know, nhibernate cannot help there. Every hql query gets converted into sql suitable for underlying database.

I could be wrong there (may not have explored nhibernate enough) but i have never seen such a thing (querying memory objects) in my experience with NH for last year and a half.

Let me understand, in your experience, nHibernate cannot create this Sql Query:

SELECT Parents.*

FROM Parents

WHERE Parents.idParent in

(SELECT ParentChildren.idParent
FROM ParentChildren
WHERE idChild = @childID)

?

Which returns (in SQL) the Parent Record.

Yes it can but this is not what you posted originally. There was no mention of ParentChildren table in between.

What you have mentioned in your last post is do-able. But again everything must be in underlying database to run a query on.

By design, there was no database structure include in the original post because I'm querying objects not the db...and that's what I request help with.

'Doable'?

Objects only? I cannot help there. May be somebody with more experience with NH can.

Solution: change HQL to use elements of Parent.Children.

HQL:
from Parent p where (from Child c where c.Id = :childID) in elements(p.Children)