Edit: topic title got concatenated, it should be "path expression ends in a composite value" but no composite key


Some mapping:

<class name="MyProject.Child, MyProject" table="Child">
<id name="ID" access="property" column="ID" type="Int64" unsaved-value="0">
<generator class="hilo">
<param name="max_lo">9</param>
</generator>
</id>
......
.......
</class>

query:

select a.ID, a.Name, a.OpenDate, count(*), sum(c.Amount)) from Parent a inner join a.Child as b, Granchild c
where c.ChildID = b.ID and b.Parent = ?
group by a.ID, a.Name, a.OpenDate

this fails with a query exception "Path expression ends in a composite value".
I think its the "where c.ChildID = b.ID" that causes it, because if I change the query to b.Id it complains about not being able to resolve Id, which I would expect.

None of the objects have a composite key, in fact they are all identical to the above mapping, so why does it complain about a composite value ? how is that even possible ? I can't find anything that relates to this.

I'm trying to achieve this:
select a.ID, a.NAME, a.OPENDATE, count(c.ID) 'TOTAL COUNT', sum(c.AMOUNT) 'TOTAL AMOUNT'
from PARENT a join CHILD b on a.CHILD = b.ID
join GRANCHILD c on b.ID = c.CHILDID
where b.PARENT = ?
group by a.ID, a.NAME, a.OPENDATE

Further Info: I found some references to ID being a reserved word in HQL, I changed all ID properties to be UID but the query still causes the same error.

Can I supply any more information to progress with this ?

You get this exception, because the result of that query isn't a type NHibernate knows. You can use AddScalar(...) to retrieve the raw data without fetching them into objects. Or you can use a ResultTransformer (AliasToBean) to fetch the data into custom typed objects, where the properties have the same names as the retrieved columns.

Thanks for the reply.

This gets complicated, because I have to use Castle on top of NHibernate, the resulting type of the query is registered, but for whatever reason isn't being passed to NHibernate.

I'll have to shift my focus to what Castle is doing to figure it out.

You could try to use a query like that:



where MyType is your class which has a constructor that takes the columns in this query as parameters.

Perhaps this way works...

Typhos, thats exactly what I'm doing, I need to find out why AR hasn't mapped MyType.