Re: Uregntly need help for thesis: Batch reading of collection with lazy OneToOne relation

by tware :: Rate this Message:

Hi Frank,

I am not arguing that downcasting is not a useful feature. In fact, when our
JPA 2.0 release is done, I suspect it will be fairly high on the list of the
features we consider implementing.

What I am suggesting is that for a performance benchmark to merit including a
feature like this the benchmark would have to be a fairly far reaching benchmark
- likely a bigger benchmark than one would write as part of a bachelor's thesis.
Mario has addressed this question in his previous email.

-Tom

Frank Schwarz wrote:

> Hi Mario,
>
> the query key has to be defined on Partner pointing to Employee instead of
> Role. Please have a look at
> http://code.google.com/p/oopex/source/browse/trunk/modules/eclipselink1-jpa/src/queries-downcasts/java/oopex/eclipselink1/jpa/queries/DowncastsMain.java#139.
> I never tried this for defining Join-Reads/Batch-Reads, though.
>
> @Tom: Using downcasts in queries is, from my point of view, something quite
> natural if you design your model in a truly object oriented way. Reiterating
> that this feature nobody is needing, does not make disappear. The other
> feature, Mario is looking for, might be called "fetch-plans/plans" - as in
> the old JDO days ;-). See
> http://wiki.eclipse.org/EclipseLink/Development/JPA/NestedFetchGroups, last
> item in the open issues list. Also this feature(-request) I see frequently
> in projects when there is a CRUD-style rich client.
>
> -- Frank
>
> Meet me at JFS2009 http://www.java-forum-stuttgart.de/
>
>
> Mario Sandro Schwarz wrote:
>> I did already try it with a customizer based on the workaround from Doug
>> Clarke "Accessing un-mapped attributes using QueryKey "
>> (http://wiki.eclipse.org/EclipseLink/Development/JPA/QueryDownCast). The
>> role entity class was annotated with this Customizer:
>>
>>
>

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