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From Craig L Russell <Craig.Russ...@Sun.COM>
Subject Re: Minutes: JDO TCK Conference Call Friday, July 14 9 am PST
Date Mon, 17 Jul 2006 17:03:10 GMT
Hi Jörg,

On Jul 17, 2006, at 9:26 AM, Jörg von Frantzius wrote:

> Hello Craig,
>
> if I understand things right, you changed your mind and now you  
> don't see a any problem with JPOX's automatic nulling out of FKs?
Yes, I have changed my mind on this issue.

> If that's the case, then I wonder why a user would want to have FK  
> constraints in his schema at all? They wouldn't be of much use then.

If only using JDO, I agree. What matters is the consistency of the  
object model, which is managed by the JDO implementation without help  
from the database. But seldom is JDO the only access path to the  
database.
>
> I may also add that, as far as I know, JPOX nulls out only for one- 
> one bidirectional, not for one-many, so there would be some  
> inconsistency of behaviour here.

Interesting point, but without another level of detail, it's hard to  
evaluate this statement.

Regards,

Craig
>
> Regards,
> Jörg
>
> Craig L Russell schrieb:
>>
>> 2. Deletion of objects when foreign-key is present (JDO-392) (any  
>> and all) It seems that there are two different issues: managing  
>> the memory model and managing the database. Craig opines that the  
>> general case of consistency is already covered in the chapter on  
>> mapping, requiring that the object model be consistent after a  
>> flush. Object model consistency would disallow a reference to a  
>> deleted object, so the natural behavior would be to nullify the  
>> reference to the deleted object. For to-many relationships mapped  
>> to a foreign key on the other side, the consistency rule would  
>> delete the reference from the collection on the one- side of the  
>> relationship. So it seems that the JPOX behavior as originally  
>> reported is consistent and we might simply document it in the  
>> specification.
> Why does object model consistency disallow a reference to a deleted  
> object?
> <joerg.von.frantzius.vcf>

Craig Russell
Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
408 276-5638 mailto:Craig.Russell@sun.com
P.S. A good JDO? O, Gasp!


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