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From Jörg von Frantzius <joerg.von.frantz...@artnology.com>
Subject Re: Interpretation of fetch depth
Date Wed, 31 Aug 2005 18:52:06 GMT
Craig Russell schrieb:

> Hi Jörg,
>
> The fields to be fetched from the instance(s) reachable from this 
> field are governed by the fetch plan in effect. That is, the fetch 
> groups in the fetch plan are used to determine the set of fields to be 
> fetched. So all of the primitive fields in the fetch groups would be 
> fetched (and none of the relationship fields, as you pointed out).

I take it that that would be equivalent to FetchPlan.VALUES then? I'm 
not sure about that, as FetchPlan.VALUES is not documented overly 
verbose in the Javadocs and the spec ;)

>
> If you want only the primary key to be fetched, then you should 
> specify fetch groups in your fetch plan that do not include "default" 
> and don't include any of the other fields in the reached class.
>
> Regards,
>
> Craig
>
> On Aug 31, 2005, at 10:47 AM, Jörg von Frantzius wrote:
>
>> Hi,
>>
>> in the spec, in §12.7.2 it reads
>>
>>    "Recursive fetch group references are controlled by the fetch-depth
>>    attribute. A fetch-depth of 0 will fetch the whole graph of
>>    instances reachable from this field. The default is 1, meaning that
>>    only the instance directly reachable from this field is fetched."
>>
>> For a fetch-depth of 1, when we fetch such a reachable instance, what 
>> fields of that instance should be fetched exactly? All I know is we 
>> must not fetch any of its object fields, as recursion stops here. One 
>> solution would be to fetch only the primary key, would that be in the 
>> sense of the specification? It might seem strange, but for my 
>> application this makes the most sense.
>>
>> Regards,
>> Jörg
>>
>> -- 
>> __________________________________________________________
>> Dipl.-Inf. Jörg von Frantzius  |            artnology GmbH
>>                               |                Milastr. 4
>> Tel +49 (0)30 4435 099 26      |              10437 Berlin
>> Fax +49 (0)30 4435 099 99      |  http://www.artnology.com
>> _______________________________|__________________________
>>
>>
>
> 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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