Re: foundations of relational theory?

Originally posted by Bob Badour

> "andrewst" <member14183_at_dbforums.com> wrote in message

> news:3522589.1067088824_at_dbforums.com"]news:3522589.1067088824_at_d-
> bforums.com[/url]...

> > Originally posted by Mike Preece

> > > And 'normalisation'? You have to fit your data into a 2
> dimensional

> > > structure although you get the sneaking suspicion sometimes
> that it's

> > > actually a lot more difficult to do so than it should be
> somehow?

> > > That's because you're insisting on making life difficult for
> yourself.

> > > Well go on if that's what rocks your boat. Knock yourself
> out!

> > >

> > Leaving aside the 2-dimensional fallacy, which Marshall has
> already

> > addressed, what is it you imagine is so difficult about 1st
> normal form,

> > which is what I think you are suggesting is difficult?

> > When you have an Invoice with many Invoice Lines, in Pick you
> create a

> > MV item for the lines. With an RDBMS, we create a separate
> table for

> > the lines. That's all. No more difficult or more easy, just
> different.

>

> Or a relation valued attribute with no extra table. Again, no more

> difficult; although, the result is much easier and much more
> predictable to

> use.

What *is* a relation valued attribute? How does it differ from a multivalued attribute in Pick? I guess they're logically the same thing. How is a relation valued attribute physically represented in SQLrelational ?

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