That looks like the way to go Fedor. I have another issue that I want to
bring up at this point. Both Torque's use a type attribute for columns with
values like "INTEGER", "VARCHAR", "VARBINARY" etc. This ties a little too
closely to (a specific variant of ) SQL for my liking, Wouldn't it be better
to use Java-like types, e.g. "int", "string", "date", etc., and then have
separate mapping files for each db, e.g. for Oracle:
<db-mapping db="Oracle">
<types>
<type name="int" db-name="NUMBER"/>
...
</types>
</db-mapping>
Thoughts?
Frank
----- Original Message -----
From: "Fedor Karpelevitch" <[EMAIL PROTECTED]>
To: "Turbine" <[EMAIL PROTECTED]>
Sent: Thursday, September 14, 2000 9:40 PM
Subject: Re: Foreign Keys in Torque
> > > Is there a way in Torque to handle foreign key like this:
> > >
> > > FOREIGN KEY (A, B) references TABLE2 (A, B)
> > >
> > > if yes, how should I describe it in XML schema?
> > > Does it make sense to make Foreign keys entities on their own, not
just
> > > attributes? This would allow for more flexibility, because FKs _are_
> > > actually entities...
> > >
> > >Opinions?
> > >
> > >fedor.
> >
> >In newtorque foreign keys are only allowed to be one column, but it can
> >reference a different column in the foreign table. That is FOREIGN KEY
(A)
> >references TABLE2 (B). This is about as far as the flexibility goes at
the
> >moment.
> >
> >Maybe you can think of a nice way of representing this in the xml
> >schema file.
>
> I think the way to do it is to think of Foreign keys as entities. They
> actually are entities - look at DB diagrams. They have attributes which
> probably constitutes an entity.
>
> so thing like
> cREATE TABLE TABLE1 (
> ...
> ...
> FOREIGN KEY (A, B) REFERENCES TABLE2 (C, D)
> )
>
> would look like this in XML schema:
>
> <table name='TABLE1'>
> ...
> </table>
> <table name='TABLE2'>
> ...
> </table>
> <foreign-key name='...'>
> <primary-key-table name='TABLE2'>
> <column name='C'/>
> <column name='D'/>
> </primary-key-table>
> <foreign-key-table name='TABLE1'>
> <column name='A'/>
> <column name='B'/>
> </foreign-key-table>
> </foreign-key>
>
> Not sure about the names (as always), but you got the idea...
>
> >We'll also need to be able to add this to MapBuilder
> >so that Peers are aware of multi-column foreign keys.
>
> sure.
>
> fedor.
>
>
>
>
>
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