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From "Nat Gross" <natgr...@gmail.com>
Subject Re: ManyToMany - with a twist
Date Wed, 22 Aug 2007 16:47:23 GMT
Well, not exactly.
However I happened to pageDn from that link you provided and in 7.7 I found
the answer!
http://openjpa.apache.org/docs/nightly/manual/manual.html#ref_guide_mapping_jpa_onemany

This is an openjpa enhancement over the standard spec.

Thanks,
natG

On 8/22/07, Patrick Linskey <plinskey@gmail.com> wrote:
>
> Hi,
>
> It sounds like you're looking for OpenJPA's constant join behavior.
> You can read about it at
>
> http://openjpa.apache.org/docs/nightly/manual/manual.html#ref_guide_mapping_notes_nonstdjoins
>
> -Patrick
>
> On 8/21/07, Nat Gross <natgross@gmail.com> wrote:
> > [In an existing ejb 2 application] I have an interesting manytomany
> > scenario.
> >
> > Class EntityA with a 1 field Integer pk can relate to other instances of
> > itself in more than one way.
> > Not only can it have many  EntityA children and have many EntityA
> parents it
> > can have the SAME EntityA Parent/Child more than once.
> > Each EntityA needs a reason as to why it relates to the other EntityA.
> > (Suppose EntityA is a Person that can relate to another Person in more
> than
> > one way, say a cousin,  a spouse, employer, business partner. [ahem<g>])
> > Currently I have a table, ARELATIONS, with three Integer fields: srcPK,
> > targetPK, relateType. All three fields make up the PK. Currently I am
> > manually controlling the joins of this table with EntityA. I would like
> to
> > utilize jpa to do this.
> >
> > Also important to note is that it is not enough for the end-user to
> simply
> > fetch related EntityA records, the *reason* (relateType) is also
> important.
> >
> > Basically I should be able to define two OneToMany Unidirectional
> > Collection<Arelations> fields in EntityA, but whatever I try with
> Toplink I
> > get different problems. (Basically, Toplink wants yet another
> intersection
> > table, which I don't want.)
> > I hope openjpa has a better solution.
> > Please adivse.
> >
> > Thanks
> > natG
> >
>
>
> --
> Patrick Linskey
> 202 669 5907
>

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