Re: foundations of relational theory? - some references for the truly starving

In article <CUYmb.86063$Ms2.64480_at_fed1read03>, daveb <davebest_at_SuPsAaM.net> writes
>"Ross Ferris" <ross_at_stamina.com.au> wrote in message
>news:26f6cd63.0310260541.7a6a9af9_at_posting.google.com...
>> "Bob Badour" <bbadour_at_golden.net> wrote in message
>news:<GumdnaAjFvrJmQaiU-KYvg_at_golden.net>...
>> > The values in a foreign key reference are redundant because they appear
>in
>> > multiple relations. In this case, the redundancy is appropriate and
>> > necessary to represent the data.
>>
>> Interesting "admission", or at least an observation. Of course this
>> redundancy is ONLY necessary because of the "flat earth" nature of SQL
>> implementations.
>>
>> If the data were stored in a multi-valued database, or even an XML
>> data store, then the redundant data could be removed.
>
>No, you have merely encoded the redundancy in the structural relationship.
>
Where? There is no key (foreign or otherwise) with which to do the link, because there is no need to do a link.

So yes there is a structural relationship, but there is no redundancy because no information is stored - it is IMplicit in the data store, not EXplicit.

Cheers,
Wol

-- 
Anthony W. Youngman - wol at thewolery dot demon dot co dot uk
Witches are curious by definition and inquisitive by nature. She moved in. "Let 
me through. I'm a nosey person.", she said, employing both elbows.
Maskerade : (c) 1995 Terry Pratchett