Re: Strange error message

Chuck Hill <[email protected]>
Newsgroups gmane.comp.web.webobjects.eof
Organization Global Village Consulting, Inc.
Message-ID <[email protected]>
Hi Anjo,

Anjo Krank wrote:

> Hi Chuck,
> 
> Am Dienstag, 08.10.02, um 19:59 Uhr (Europe/Berlin) schrieb Chuck Hill:
> 
>> Ah Ha!  I know the answer.  EOs in an inheritance hierarchy MUST MUST 
>> MUST have unique primary keys.  That is the only way that EOF can 
>> differentiate which class an object is.  In your case
>>
>> RootClass ----> EntityA
>>           ----> EntityB
>>
>> No object of EntityA, EntityB (or RootClass if not abstract) can have 
>> the same PK.
> 
> 
> I don't understand that: AFAIK, a EOGlobalID contains nor only the PK, 
> but also the entity.

Not exactly.  It has the *root* entity in the hierarchy.

> So EOF should be able to get the correct object 
> when you have horizonatl inheritance?

EOF can always get the correct object provided that there are no duplicate PKs 
anywhere in the hierarchy.


> Is this supposed behaviour or has anyone filed a bug report?
> 

It appears to me that this is by design, not a bug.


Chuck


>>   If EOF fetches an instance of EntityA with a PK of 1000, and then 
>> fetches an instance of EntityB with a PK of 1000 it will think 
>> (because the EOGlobalID is the same) that the EntityB instance is 
>> actually the EntityA instance.
>>
>>
>> Chuck
>>
>>
>> Camille Troillard wrote:
>>
>>> Hi Chuck,
>>> On Tuesday, Oct 8, 2002, at 19:34 Europe/Paris, Chuck Hill wrote:
>>>
>>>> I've only seen this happen when inheritance was involved which, I 
>>>> believe, you said was not.  Very strange.
>>>
>>> Yes, it seems like it.
>>> I didn't explained my problem correctly:
>>> I actually said that the entities cannot be casted from one to other. 
>>>  But they have the same root class.
>>> I have posted a message to Jonathan on eof mailing list, that details 
>>> the steps to reproduce to have the problem.
>>> You must have received a copy vie the mailing list manager.
>>> Best Regards,
>>> Camille
>>>
>>>> Camille Troillard wrote:
>>>>
>>>>> Hi Anjo,
>>>>> First of all, thank you for the help.
>>>>> On Tuesday, Oct 8, 2002, at 18:51 Europe/Paris, Anjo Krank wrote:
>>>>>
>>>>>> This seems like another case of the problem you had with your PKs 
>>>>>> for the reference entities - for which I also have no explanation?
>>>>>
>>>>>
>>>>> I have more infos about my problem:
>>>>> Here are the steps I did to reproduce something "weird".
>>>>> 1. Create an "ODAgency" object.
>>>>> The object has been correctly created in the database (ID: 1000004).
>>>>> 2. Fetch the "ODAgency" objects.
>>>>> Only 2 objects, there should be 3.
>>>>>     A.  I don't see the object I just inserted (though it is in the 
>>>>> DB).
>>>>>     B.  The first one in an ODAgency, the second one is ...  a 
>>>>> ODAdvertiser !!!!
>>>>>         With ID, guess what ??? ID: 1000004 (same as the newly 
>>>>> created advertiser).
>>>>> The thing is that is seems that EOF gets confused with PK.
>>>>> If two entities raws have the same PK, then I have a problem.
>>>>> But I can't tell why ...
>>>>>
>>>>>> Can you post that model somewhere?
>>>>>
>>>>>
>>>>> For reason you understand, I'll post you the model privately.
>>>>> If someone is willing to help me no problem, as far as I know to 
>>>>> who I post the model, then it's ok.
>>>>> Thanks again,
>>>>> Camille
>>>>> _______________________________________________
>>>>> EOF mailing list
>>>>> [email protected]
>>>>> http://www.omnigroup.com/mailman/listinfo/eof
>>>>
>>>>
>>>>
>>>>
>>>> -- 
>>>>
>>>> Chuck Hill                                 [email protected]
>>>> Global Village Consulting Inc.             
>>>> http://www.global-village.net
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> EOF mailing list
>>>> [email protected]
>>>> http://www.omnigroup.com/mailman/listinfo/eof
>>>>
>>
>>
>> -- 
>>
>> Chuck Hill                                 [email protected]
>> Global Village Consulting Inc.             http://www.global-village.net
>>
>>
>>
>> _______________________________________________
>> EOF mailing list
>> [email protected]
>> http://www.omnigroup.com/mailman/listinfo/eof
>>
> 


-- 

Chuck Hill                                 [email protected]
Global Village Consulting Inc.             http://www.global-village.net
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