problem mapping differnent object to one table

[Christopher Tava]

has anyone been successfully mapping two objects to the same table??
to be more specific, i would like distinct object instances for objectAId and distinct 
object instances for objectBId in seperate queries.
 
     select distinct objectA_id from tableAB;
     select distinct objectB_id from tableAB;
 


i have used the distinct clause on the QueryCriteria class but i have not been 
successfully, because OJB wants to concatenate objectAId and objectBid together in the 
following sql;
 
     select distinct objectA_id, objectB_id  from tableAB;
 
why does OJB combine objectA_id and objectB_id in the select clause of the query if 
two class descriptors exist for the same table?  
 
i did try the reportQuery to restrict the columns.  i got the sql that is generated 
seems to be correct.  however ojb is throwing an invalid class cast exception which i 
don't understand.
 
any thoughts are much appreciated?
 
 
 
<!-- Definitions objectA -->
 <class-descriptor
  class="objectA"
     table="tableAB"
  >
   <field-descriptor id="1"
         name="objectAId"
         column="OBJECTA_ID"
         jdbc-type="INTEGER"
         primarykey="true"         
      />
 </class-descriptor>
 
<!-- Definitions objectB -->
 <class-descriptor
  class="objectB"
     table="tableAB"
  >
   <field-descriptor id="1"
         name="objectBId"
         column="OBJECTB_ID"
         jdbc-type="INTEGER"
         primarykey="true"         
      />
 </class-descriptor>



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