Hi All,

A few weeks ago, I posted a question about "batch fetching" support (http://sourceforge.net/forum/message.php?msg_id=3110550).

The solution suggested to me was to use "from Parent p left join fetch p.Children" syntax in a query.

This pretty much achieves what I need in terms of reducing the SQL calls to one, however it introduces a new problem.

With regards to the following query,



Lets say that there are 3 'header' rows, each one having say '5' children. The resulting orders IList will contain 15 clsOrderHeader objects. Basically, 5 instances of each one (ie one for each detail row).

Can someone please tell me if this is expected behaviour? Is there a way to reduce it to the correct amount? Should I be manually filtering it?

For brevity, I've not included my hbm.xml files but obviously am more than happy to if it will help. I don't think that this is the problem though because, when I use 'normal' CreateCriteria sytax, the code runs fine.

Thanks very much for your help.



Damien Sawyer

Yes, this is how Java Hibernate behaves too - essentially it translates the rows returned by the database query into objects. That SQL query returns 15 rows, so you get 15 objects in the list (but only 3 of them distinct). You have to filter the result set manually (using an ISet for example).

Thanks Sergey

Nice feature, HQL is powerful.

I had/have the same problem as damien but I go another level into the hierarchy.

What I was trying to do is:

<b>HQL</b>: from Grandparent Grandparent left join fetch Grandparent.Parent Parent left join fetch Parent.Children

This results in the correct SQL query but NHibernate seems to not set Gradparent's Parent property whereas a simple 'from Parent Parent left join fetch Parent.Children' would.

Any ideas?