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Posted to ojb-user@db.apache.org by Ollie Rutherfurd <ol...@rutherfurd.net> on 2003/07/10 21:48:28 UTC
mapping M:N relationship, with a twist
Hi,
I'm trying to setup an M:N mapping, however I can't follow the examples in the
tutorial, as I've got a twist. Here's what the relationship looks like:
Category <-> LinkTable <- Item
The hitch is that rows in LinkTable may either refer to rows in the Item
or Category table (depending on a column value). In otherwords, Category may
contain 0 or more Categories as well as 0 or more Items. Both Category and Item
may be contained by 0 or more Categories.
If anyone had any suggestions or pointers on how to best achieve this type of
mapping, I'd really appreciate it!
Thanks,
-Ollie
--
Ollie Rutherfurd
oliver@rutherfurd.net
http://www.rutherfurd.net/
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Re: mapping M:N relationship, with a twist
Posted by Matthias Laube <ml...@gmx.de>.
It looks like you should decompose your Category - Item relationship
into 2 m:n relationships
Category - LinkTable - Category
Category - LinkTable - Item
--
Matthias Laube
mlaube@gmx.de
Ollie Rutherfurd wrote:
> Hi,
>
> I'm trying to setup an M:N mapping, however I can't follow the
> examples in the tutorial, as I've got a twist. Here's what the
> relationship looks like:
>
> Category <-> LinkTable <- Item
>
> The hitch is that rows in LinkTable may either refer to rows in the Item
> or Category table (depending on a column value). In otherwords,
> Category may contain 0 or more Categories as well as 0 or more Items.
> Both Category and Item may be contained by 0 or more Categories.
>
> If anyone had any suggestions or pointers on how to best achieve this
> type of mapping, I'd really appreciate it!
>
> Thanks,
> -Ollie
>
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