Criteria: query a class and return list based on a property

yannickc · **Joined:** Wed Oct 08, 2008 10:11 am **Posts:** 3

I'm having difficulties constructing a criteria typed query.

Let's say we have a Hierarchy class with 2 properties called Parent and Child of a certain class, Foo for instance. The Foo class has no knowledge of Hierarchy.

I want to query the Hierarchy class to find all childs with a certain parent.

Code:

ICriteria criteria = session.CreateCriteria(typeof(Hierarchy));
criteria.Add(Expression.Eq("Parent", parent));

This would return all the Hierarchy objects with the parent, but I want a list of Foo. (without looping through the Hierarchy objects and filtering the childs out)

But for the love of God, I can't figure out how, I've been fooling around with Projections and ResultTransformers, without success.

gonzao_diaz · **Joined:** Mon Nov 26, 2007 2:29 pm **Posts:** 443

If you don't want to traverse the graph of objects Jav-style, use HQL instead, specifying parent and child in the select list.

When more than one thing is put in the select list of an HQL query, Hibernate returns the results as an array of Object[].
Simply traverse that array, not minding the repeated parent.