Re: does a table always need a PK?

Hi Morten,

more info available on www.thethirdmanifesto.com.

regards,
Lauri Pietarinen

Morten Gulbrandsen wrote:

>Leandro GuimarÒ£es Faria Corsetti Dutra <lgcdutra_at_terra.com.br> wrote in message news:<pan.2003.08.26.15.14.06.524358_at_terra.com.br>...
>
>
>>Em Mon, 25 Aug 2003 04:55:02 +0000, Heikki Tuuri escreveu:
>>
>>
>>
>>>we discussed the 'correct' definition of 'relational' in
>>>comp.databases.theory with several people. I think the concept is vague. For
>>>example, Codd's 12 principles are not formulated as mathematical axioms.
>>>
>>>
>> No, but some of them have clear mathematical implications --
>>for example, SQL can't be relational 'cause its tables aren't relations
>>but bags -- while some others are more related to good design.
>>
>> In any way, Codd's work is somewhat obsolete. I'd look to D&D's _TTM_.
>>
>>
>
>
>I think I found D&D's _TTM_
>
>http://www.acm.org/sigmod/record/issues/9503/manifesto.ps
>
>The Third Manifesto
>Hugh Darwen and C.J. Date
>
>The article has some interesting observations on SQL
>as a relational database Model language.
>
>
>Correct me please!
>
>Yours Sincerely
>
>Morten Gulbrandsen
>
>
Received on Mon Sep 01 2003 - 15:10:29 CEST