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Posted to ojb-user@db.apache.org by Lynn Monson <ly...@nextpage.com> on 2003/03/14 03:22:51 UTC

Implementing Single Table Aggregation in OJB

Could anyone tell me how to implement the Single Table Aggregation pattern for a 1:1 relation using OJB?  RowReaders seem to solve the problem for reading, but I'm stumped as to how to write to such a table.
 
The pattern is found here:
http://www.objectarchitects.de/ObjectArchitects/orpatterns/MappingObjects2Tables/SingleTableAggregation/
 
Any help is *greatly* appreciated.

Re: Implementing Single Table Aggregation in OJB

Posted by Thomas Mahler <th...@web.de>.

Hi Lynn,

You have to tell OJB to use a PersistenField implementation supporting 
this in OJB.properties first, as it is not yet implemented in the 
default implementation:

PersistentFieldClass=org.apache.ojb.broker.metadata.fieldaccess.PersistentNestedFieldMaxPerformanceImpl

if your class has an attribute "address" of type Adress,
the mapping for the "street" attribute of "address" would look like follows:

       <field-descriptor
          name="adress->street"
          column="ADR_STREET"
          jdbc-type="VARCHAR"
       />

cheers,
Thomas

Lynn Monson wrote:
> Could anyone tell me how to implement the Single Table Aggregation pattern for a 1:1 relation using OJB?  RowReaders seem to solve the problem for reading, but I'm stumped as to how to write to such a table.
>  
> The pattern is found here:
> http://www.objectarchitects.de/ObjectArchitects/orpatterns/MappingObjects2Tables/SingleTableAggregation/
>  
> Any help is *greatly* appreciated.
>

Re: Implementing Single Table Aggregation in OJB

Posted by Joerg Lensing <in...@softcon-lensing.de>.

Lynn Monson schrieb:

>Could anyone tell me how to implement the Single Table Aggregation pattern for a 1:1 relation using OJB?  RowReaders seem to solve the problem for reading, but I'm stumped as to how to write to such a table.
> 
>The pattern is found here:
>http://www.objectarchitects.de/ObjectArchitects/orpatterns/MappingObjects2Tables/SingleTableAggregation/
> 
>Any help is *greatly* appreciated.
> 
>
>
>  
>
Hello Lynn,
can you describe your object-model -respectively the part you want to 
use the Single Table Aggregation pattern?

Joerg