Re: Interesting article: In the Beginning: An RDBMS history
Date: Tue, 4 Apr 2006 09:43:48 +0300
Message-ID: <e0t4ij$bfh$1_at_emma.aioe.org>
"paul c" <toledobythesea_at_oohay.ac> wrote in message
news:xPbYf.218029$B94.60669_at_pd7tw3no...
> x wrote:
> > "paul c" <toledobythesea_at_oohay.ac> wrote in message
> > news:GX_Wf.201803$sa3.143853_at_pd7tw1no...
> >
> Thanks for that, anyway. Maybe I was dreaming about what I thought I
> read. I see the word 'relation' doesn't appear in the quotes but maybe
> this doesn't matter (assuming that those drafts' other words appear in
> the actual standard with the same intended meanings).
> Codd, in his 1970 paper, pg 80, said: "Accordingly, we propose that
> users deal, not with relations which are domain-ordered, but with
> relationships which are their domain-unordered counterparts". In the
> next paragraph he says: "To sum up, it is proposed that most users
> should interact with a relational model of the data consisting of a
> collection of time-varying relationships (rather than relations".
> It seems that by using the word "relationship" he was merely trying to
> draw a line between mathematical relations that have ordered domains and
> ones that replace the ordering with names as well as between logical and
> physical representations. (By "most users" in the second sentence I'm
> guessing that he was talking about everybody except DBA's.) Also seems
> that what he meant by 'relationship' was roughly what we call 'relation'
> today.
> So I guess it would be reasonable for the standard to use "relationship"
> as long as it clarifies where it uses that word in some special sense,
> such as when talking about functional dependencies which seems to me to
> throw 'relationship', 'table' and 'columns' up in the air and let them
> land on the floor however they may. That heading 4.14.4 about
> "Relationships between tables" seems murky since Codd's 1970 paper
> AFAICT mentions tables only in the sense of 'data description tables'
> (presumably in the dictionaries of the hierarchical products of those
> times, the 1969 paper doesn't seem to mention them at all).