Ordering by attribute of associated entity

stue · **Joined:** Tue Aug 26, 2008 12:18 pm **Posts:** 9

Hello,

I have very simple question, but I couldn't find answer anywhere.
How can I order the result of Criteria query by the atribute of asociated entity?

For example if you want to order the result of Childs entities by the age of their Mother, where Mother is many-to-one asociated entity.
I succed when I did this by HQL: "from Child child order by child.mother.age asc";

But I need to work with Criteria object, so I need something like this:

Code:

 DetachedCriteria crit = DetachedCriteria.forClass(Child.class);
 crit.addOrder(Order.asc("mother.age"));

But this doesn't work, hibernate throws exception with the message, that attribute 'mother.age' of class Child is unknown.
Does anybody knows, if this kind of ordering is possible in Criteria queries?

Thanks in advance.

sumit.tyagi · **Joined:** Tue Jan 06, 2009 5:03 am **Posts:** 7

If you always want ordering by age in that case you can specify this in annotation above collection in your Parent class

@OrderBy(age) .

Then child elements will always be in order by age.
May be helpful

stue · **Joined:** Tue Aug 26, 2008 12:18 pm **Posts:** 9

Thanks, but it is not, what I wask asking about.
This annotation only causes, that all childs in collection will be ordered.

What do I need is to order in criteria query by attribute of associated entity (e.g. order childs by age of their mothers), as I'm describing in my first, original post.

jpkrohling · **Posted:** Fri Sep 25, 2009 11:13 am

You missed the createAlias :-)

Code:

      DetachedCriteria c = DetachedCriteria.forClass(Child.class)
         .createAlias("mother", "m")
         .addOrder(Order.asc("m.age"));

http://docs.jboss.org/hibernate/core/3. ... teria.html - Section 15.4

stue · **Joined:** Tue Aug 26, 2008 12:18 pm **Posts:** 9

Thank you very much, jpkrohling.

This was exactly what I was looking for!