Re: OJB not returning the correct child types.

Hi Gautam,

as said in my previous post in thread "OJB: Identity equals method 
impl." you should use the "normal" TPS inheritance without a FK field 
and without "extent-class" declaration within TPS (and don't override 
fields in the sub-classes):

<class-descriptor
     class="Thing"
     table="THINGS">

     <field-descriptor
         name="id"
         column="ID"
         jdbc-type="INTEGER"
         primarykey="true"
         autoincrement="true"
         />

     <field-descriptor
         name="name"
         column="NAME"
         jdbc-type="VARCHAR"
         size="255"
         />

     <field-descriptor
         name="drawerId"
         column="DRAWER_ID"
         jdbc-type="INTEGER"
         access="anonymous"
         />

</class-descriptor>

<class-descriptor
     class="Toy"
     table="TOYS">

     <field-descriptor
         name="id"
         column="ID"
         jdbc-type="INTEGER"
         primarykey="true"
         autoincrement="false"
         />

     <field-descriptor
         name="category"
         column="CATEGORY"
         jdbc-type="VARCHAR"
         size="255"
         />
     </field-descriptor>

     <reference-descriptor
         name="super"
         class-ref="Thing"
     >
         <foreignkey field-ref="id"/>
     </reference-descriptor>

</class-descriptor>

<class-descriptor
     class="Book"
     table="BOOKS">

     <field-descriptor
         name="id"
         column="ID"
         jdbc-type="INTEGER"
         primarykey="true"
         autoincrement="false"
         />

     <field-descriptor
         name="author"
         column="AUTHOR"
         jdbc-type="VARCHAR"
         size="255"
         />

     <field-descriptor
         name="isbnCode"
         column="ISBN_CODE"
         jdbc-type="VARCHAR"
         size="255"
         />

     </field-descriptor>

     <reference-descriptor
         name="super"
         class-ref="Thing"
     >
         <foreignkey field-ref="id"/>
     </reference-descriptor>

</class-descriptor>


<class-descriptor
     class="Drawer"
     table="DRAWER">

     <field-descriptor
         name="id"
         column="id"
         jdbc-type="INTEGER"
         primarykey="true"
         autoincrement="true"
         />

     <collection-descriptor
         name="stuffInDrawer"
         element-class-ref="Thing"
         >
         <inverse-foreignkey field-ref="drawerId"/>
     </collection-descriptor>
</class-descriptor>


The FK field "drawerId" in class Thing (of the 1:n reference in Drawer) 
is declared as anonymous. Please read carefully the section about how 
anonymous keys work to avoid problems
http://db.apache.org/ojb/docu/guides/advanced-technique.html#How+do

regards,
Armin

Virgo Smart wrote:
> Hello,
> 
> I am facing an issue when trying to retrieve the Drawer object.
> Instead of retrieving a collection of Toy and Book instances in the stuffInDrawer attribute, collection containing Thing instances is returned.
> 
> Following is the class descriptor that is used.
> 
> <class-descriptor
>     class="Thing"
>     table="THINGS">
> 
>    <extent-class class-ref="Toy"/>
>    <extent-class class-ref="Book"/>
> 
>     <field-descriptor
>         name="id"
>         column="ID"
>         jdbc-type="INTEGER"
>         primarykey="true"
>         autoincrement="true"
>         />
> 
>     <field-descriptor
>         name="name"
>         column="NAME"
>         jdbc-type="VARCHAR"
>         size="255"
>         />
> 
>     <field-descriptor
>         name="drawerId"
>         column="DRAWER_ID"
>         jdbc-type="INTEGER"
>         access="anonymous"
>         />
> 
> </class-descriptor>
> 
> <class-descriptor
>     class="Toy"
>     table="TOYS">
> 
>     <field-descriptor
>         name="id"
>         column="ID"
>         jdbc-type="INTEGER"
>         primarykey="true"
>         autoincrement="true"
>         />
> 
>     <field-descriptor
>         name="category"
>         column="CATEGORY"
>         jdbc-type="VARCHAR"
>         size="255"
>         />
> 
>     <field-descriptor
>         name="parentThingId"
>         column="THING_ID"
>         jdbc-type="BIGINT"
>         access="anonymous"
>     >
>     </field-descriptor>
> 
>     <reference-descriptor
>         name="super"
>         class-ref="Thing"
>     >
>         <foreignkey field-ref="parentThingId"/>
>     </reference-descriptor>
> 
> </class-descriptor>
> 
> <class-descriptor
>     class="Book"
>     table="BOOKS">
> 
>     <field-descriptor
>         name="id"
>         column="ID"
>         jdbc-type="INTEGER"
>         primarykey="true"
>         autoincrement="true"
>         />
> 
>     <field-descriptor
>         name="author"
>         column="AUTHOR"
>         jdbc-type="VARCHAR"
>         size="255"
>         />
> 
>     <field-descriptor
>         name="isbnCode"
>         column="ISBN_CODE"
>         jdbc-type="VARCHAR"
>         size="255"
>         />
> 
>     <field-descriptor
>         name="parentThingId"
>         column="THING_ID"
>         jdbc-type="BIGINT"
>         access="anonymous"
>     >
>     </field-descriptor>
> 
>     <reference-descriptor
>         name="super"
>         class-ref="Thing"
>     >
>         <foreignkey field-ref="parentThingId"/>
>     </reference-descriptor>
> 
> </class-descriptor>
> 
> 
> <class-descriptor
>     class="Drawer"
>     table="DRAWER">
> 
>     <field-descriptor
>         name="id"
>         column="id"
>         jdbc-type="INTEGER"
>         primarykey="true"
>         autoincrement="true"
>         />
>     
>     <collection-descriptor
>         name="stuffInDrawer"
>         element-class-ref="Thing"
>         >
>         <inverse-foreignkey field-ref="drawerId"/>
>     </collection-descriptor>
> </class-descriptor>
> 
> 
> I have used the table per subclass hierarchy strategy.
> I have used SequenceManagerHighLowImpl as the sequence manager. The ids (ID column) in the TOYS and BOOKS tables are unique when the Drawer object is stored. In the sense, when a Drawer containing 3 things (2 books and 1 toy) is stored, the ids stored in THINGS table are 1, 2, and 3, where as the ids stored in BOOKS table are 1 and 2 and id stored in the TOYS table is 3.
> 
> I hope I have provided sufficient details to debug the issue. Could anyone please point me as to where am I going wrong or if there is any way to circumvent the problem ?
>  
> Thanks and Regards,
> Gautam.
> 
> 
>  
>