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Posted to dev@openjpa.apache.org by Tim McConnell <ti...@gmail.com> on 2009/02/23 00:03:07 UTC
@PersistentCollection question
Hi, I see a number of inconsistencies in the OpenJPA Junit testcases concerning
the usage of the @PersistentCollection annotation on a java.util.List variable
without the @OrderBy annotation. If I'm interpreting this scenario correctly,
without the @OrderBy annotation there is no column in the database used for
ordering when retrieving the List back into memory, and thus there can be no
assumption made about that order in the testcase. This appears to be why these
testcases work on some database and not others (e.g., works on Derby, fails on
PostgreSQL). Am I interpreting it correctly ?? Or am I missing something obvious ??
--
Thanks,
Tim McConnell
Re: @PersistentCollection question
Posted by Kevin Sutter <kw...@gmail.com>.
+1 on option (a) as well. Since we already have tests for the @OrderColumn
mechanism, let's not duplicate that effort.
On Mon, Feb 23, 2009 at 10:17 AM, Jeremy Bauer <te...@gmail.com> wrote:
> Tim,
>
> I think you've found a valid problem in the test cases. The basic use of
> PersistentCollection does not enforce ordering so results will vary for
> each
> database.
>
> Depending on what is being tested you could:
>
> a) Modify the validation code to validate the collection based on
> non-deterministic ordering of data. This may be the best option since the
> OpenJPA execution path being tested is the same.
>
> b) Add explicit column ordering using @OrderBy. This requires the use of a
> persistent field/property that is order-able. Possibly the Id field? This
> also requires that the elements in you your list are in that order. Might
> be get kind of messy - and this changes the OpenJPA execution path.
>
> c) As Pinaki mentioned, use synthetic ordering. This can be achieved with
> @OrderColumn. An 'order' column will be added to the collection table and
> OpenJPA will use this column to manage the order of the collection. If
> changing the execution path isn't a big concern, this is likely the best
> option. However, OpenJPA has OrderColumn specific tests, so I vote for
> option a) to keep the non-ordered path(s) covered, if possible.
>
> -Jeremy
>
> On Mon, Feb 23, 2009 at 8:41 AM, Pinaki Poddar <pp...@apache.org> wrote:
>
> >
> > afaicr, OpenJPA was maintaining ordering for elements for field that is
> > declared (or even instantiated) as java.util.List. It has the capability
> of
> > creating synthetic column to maintain element ordering even when @OrderBy
> > or
> > some other ordering spec is absent.
> >
> >
> >
> >
> > Tim McConnell wrote:
> > >
> > > Hi, I see a number of inconsistencies in the OpenJPA Junit testcases
> > > concerning
> > > the usage of the @PersistentCollection annotation on a java.util.List
> > > variable
> > > without the @OrderBy annotation. If I'm interpreting this scenario
> > > correctly,
> > > without the @OrderBy annotation there is no column in the database used
> > > for
> > > ordering when retrieving the List back into memory, and thus there can
> be
> > > no
> > > assumption made about that order in the testcase. This appears to be
> why
> > > these
> > > testcases work on some database and not others (e.g., works on Derby,
> > > fails on
> > > PostgreSQL). Am I interpreting it correctly ?? Or am I missing
> something
> > > obvious ??
> > >
> > > --
> > > Thanks,
> > > Tim McConnell
> > >
> > >
> >
> > --
> > View this message in context:
> >
> http://n2.nabble.com/%40PersistentCollection-question-tp2369556p2372385.html
> > Sent from the OpenJPA Developers mailing list archive at Nabble.com.
> >
> >
>
Re: @PersistentCollection question
Posted by Jeremy Bauer <te...@gmail.com>.
Tim,
I think you've found a valid problem in the test cases. The basic use of
PersistentCollection does not enforce ordering so results will vary for each
database.
Depending on what is being tested you could:
a) Modify the validation code to validate the collection based on
non-deterministic ordering of data. This may be the best option since the
OpenJPA execution path being tested is the same.
b) Add explicit column ordering using @OrderBy. This requires the use of a
persistent field/property that is order-able. Possibly the Id field? This
also requires that the elements in you your list are in that order. Might
be get kind of messy - and this changes the OpenJPA execution path.
c) As Pinaki mentioned, use synthetic ordering. This can be achieved with
@OrderColumn. An 'order' column will be added to the collection table and
OpenJPA will use this column to manage the order of the collection. If
changing the execution path isn't a big concern, this is likely the best
option. However, OpenJPA has OrderColumn specific tests, so I vote for
option a) to keep the non-ordered path(s) covered, if possible.
-Jeremy
On Mon, Feb 23, 2009 at 8:41 AM, Pinaki Poddar <pp...@apache.org> wrote:
>
> afaicr, OpenJPA was maintaining ordering for elements for field that is
> declared (or even instantiated) as java.util.List. It has the capability of
> creating synthetic column to maintain element ordering even when @OrderBy
> or
> some other ordering spec is absent.
>
>
>
>
> Tim McConnell wrote:
> >
> > Hi, I see a number of inconsistencies in the OpenJPA Junit testcases
> > concerning
> > the usage of the @PersistentCollection annotation on a java.util.List
> > variable
> > without the @OrderBy annotation. If I'm interpreting this scenario
> > correctly,
> > without the @OrderBy annotation there is no column in the database used
> > for
> > ordering when retrieving the List back into memory, and thus there can be
> > no
> > assumption made about that order in the testcase. This appears to be why
> > these
> > testcases work on some database and not others (e.g., works on Derby,
> > fails on
> > PostgreSQL). Am I interpreting it correctly ?? Or am I missing something
> > obvious ??
> >
> > --
> > Thanks,
> > Tim McConnell
> >
> >
>
> --
> View this message in context:
> http://n2.nabble.com/%40PersistentCollection-question-tp2369556p2372385.html
> Sent from the OpenJPA Developers mailing list archive at Nabble.com.
>
>
Re: @PersistentCollection question
Posted by Pinaki Poddar <pp...@apache.org>.
afaicr, OpenJPA was maintaining ordering for elements for field that is
declared (or even instantiated) as java.util.List. It has the capability of
creating synthetic column to maintain element ordering even when @OrderBy or
some other ordering spec is absent.
Tim McConnell wrote:
>
> Hi, I see a number of inconsistencies in the OpenJPA Junit testcases
> concerning
> the usage of the @PersistentCollection annotation on a java.util.List
> variable
> without the @OrderBy annotation. If I'm interpreting this scenario
> correctly,
> without the @OrderBy annotation there is no column in the database used
> for
> ordering when retrieving the List back into memory, and thus there can be
> no
> assumption made about that order in the testcase. This appears to be why
> these
> testcases work on some database and not others (e.g., works on Derby,
> fails on
> PostgreSQL). Am I interpreting it correctly ?? Or am I missing something
> obvious ??
>
> --
> Thanks,
> Tim McConnell
>
>
--
View this message in context: http://n2.nabble.com/%40PersistentCollection-question-tp2369556p2372385.html
Sent from the OpenJPA Developers mailing list archive at Nabble.com.