[
Date Prev][
Date Next][
Thread Prev][
Thread Next][
Date Index][
Thread Index]
[
List Home]
|
Re: [eclipselink-users] Uregntly need help for thesis: Batch reading of collection with lazy OneToOne relation
|
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:
