Re: Impossible Database Design?
Date: Thu, 18 May 2006 12:10:41 GMT
Message-ID: <5vZag.6362$S7.3169_at_news-server.bigpond.net.au>
JayDee wrote:
> Cheaper? No doubt. Better? I'm not sure.
>
> Snodgrass and Jensen and Christianson and Ben Ziv (I'm apologize if the
> names aren't correct) and others have made immense contributions to the
> field of temporal data.
Safer to say they have made immense efforts as none of it has made it into the "standard" yet.
> But have you looked at the solutions presented in the Snodgrass book?
> Yes, it's a significant achievement and, yes, it gets things done using
> SQL, and yes, it may well work. But the complexity! The redundancy!
> The work-arounds! The number of situations which result in
> 'RAISE...ERROR' with no way out! It's an absolute horror. Sure,
> convincing someone to implement such a system will keep plently of
> arcane SQL coders pounding keys for quite a long while -- but the
> chances of actually delivering something significant (Say, a design
> that results in more than 100 bi-temporal tables.) and correct are
> slim.
I agree and I believe it was a large part of the warhead use to sink the proposal to incorporate it into the standard during the 90's. I think it was Darwen who led the charge to sink the TSQL proposals.
> Date's approach seems completely reasonable to me. After all, we are
> dealing with computers, right? The best we can hope for are acceptable
> representations of continuous systems. I mean, is there really a need
> to handle a time interval as an infinite number of instants?
>
> Yes, he presented a language that isn't implemented. Judging from what
> I've seen in SQL-implementations of semi-temporal and bi-temporal data
> stores, it should be!
I have no info to frame a comment on Dates proposal (yet) but certainly the 1996 TSQL proposal was very messy. FWICT having scanned lots of the peer reviewed papers published on the subject, the whole thing did not evolve a great deal from its original inceptions which suggests the promoters were unable to come up with the simple and compelling solution that would sell itself!
Cheers, Frank. Received on Thu May 18 2006 - 14:10:41 CEST