ORDER BY column in related object

bonnyr · **Posted:** Fri Jul 14, 2006 7:24 am

Hibernate version: 3.1.2

Pseudo Mapping documents:

Code:

   <class name="NE">
                  <property name="name"/>
                  ... other properties ...
   </class>
   
   <class name="NetObj">
                  <property name="name" not-null="true"/>
                  <many-to-one name="ne" class="NE" not-null="true"/>

                  ... other properties ...
   </class>

I am attempting to run a Criteria query over NetObj where I would like the results
returned ordered by the name property of the related NE class.

From the reference manual:

Code:

List results = session.createCriteria(Domestic.class, "cat") 
   .createAlias("kittens", "kit") 
   .setProjection( Projections.projectionList() 
      .add( Projections.property("cat.name"), "catName" ) 
      .add( Projections.property("kit.name"), "kitName" ) 
   ) 
   .addOrder( Order.asc("catName") ) 
   .addOrder( Order.asc("kitName") ) 
   .list(); 

When I try this code from the manual, I keep getting errors - the referenced property is unknown.

Basically I'm doing the equivalent of:

Code:

List results = session.createCriteria(NetObj.class) 
   .setProjection( Projections.projectionList() 
      .add( Projections.property("ne.name")) 
   ) 
   .addOrder( Order.asc("ne.name") ) 
   .list(); 


or 


List results = session.createCriteria(NetObj.class) 
   .setProjection( Projections.projectionList() 
      .add( Projections.property("ne")) 
   ) 
   .addOrder( Order.asc("ne.name") ) 
   .list(); 


or 

List results = session.createCriteria(NetObj.class) 
   .addOrder( Order.asc("ne.name") ) 
   .list(); 

I get the same exception in both cases. Tracing into the Hibernate code,
it seems that H is not attempting to follow a path through the "ne" reference. Also, this happens whether or not I use the aliased version
for the specified entities (NetObj and NE).

Any help here would be greatly appreciated.

bkmr_77 · **Joined:** Tue Apr 25, 2006 12:04 pm **Posts:** 260

In your code you haven't specified 'ne' as alias. If you dont specify any alias while creating Criteria, you can use 'this' as alias.' Modifying your code as below should work.

Code:

List results = session.createCriteria( NetObj.class, "ne" ) 
   .setProjection( Projections.projectionList() 
      .add( Projections.property("ne.name")) 
   ) 
   .addOrder( Order.asc("ne.name") ) 
   .list(); 


or 


List results = session.createCriteria( NetObj.class, "ne" ) 
   .setProjection( Projections.projectionList() 
      .add( Projections.property("ne")) 
   ) 
   .addOrder( Order.asc("ne.name") ) 
   .list(); 


or 

List results = session.createCriteria( NetObj.class, "ne" ) 
   .addOrder( Order.asc("ne.name") ) 
   .list(); 

bonnyr · **Posted:** Fri Jul 14, 2006 11:31 am

bkmr_77,

I think there may be some misunderstanding: The listing which you
have corrected is not the way I intend to have the query run.

The Criteria object is given the NetObj class, but I want to use the name
property of the associated NE object's name property. Within NetObj, this
is represented by the many-to-one association named 'ne'. So, I think
the alias should have nothing to do with the NetObj. In fact, the ne.name
property I specified was to get the path to the associated object's name
property.

Also, in my listings, I think I've listed a combination where I explicitly set
an alias for the Criteria class as well as for the selected attribute to no
avail.

bonnyr · **Posted:** Sun Jul 16, 2006 7:31 pm

Can anyone help?

vadimv · **Joined:** Wed Oct 19, 2005 8:04 am **Posts:** 19

My last post is the same problem, and i got help!
Read this post:
http://forum.hibernate.org/viewtopic.php?t=962105

bonnyr · **Posted:** Mon Jul 17, 2006 9:32 am

vadim,

vadimv wrote:

My last post is the same problem, and i got help!
Read this post:
http://forum.hibernate.org/viewtopic.php?t=962105

Yes, I figured it out eventually. I did not see how an alias could
be related to an association, but looking at the source code it's
plain enough. Maybe this needs to be added to the doco.