Re: Newbie question about db normalization theory: redundant keys OK?
Date: Fri, 14 Dec 2007 11:43:05 -0800 (PST)
Message-ID: <0723c22e-9065-4be0-957e-b36c7b33faba_at_d21g2000prf.googlegroups.com>
On Dec 14, 9:36 am, David Portas
<REMOVE_BEFORE_REPLYING_dpor..._at_acm.org> wrote:
>
> I genuinely am having trouble understanding what any of this has to do
> with saying that Joe's design is "wrong". None of the problems you
> have mentioned are the usual ones given for using "artificial" keys -
> not that I've seen anyway. I don't doubt that you have some real
> issues in mind but I don't think you are explaining them very
> precisely: "The real world gets in the way" tells us nothing about why
> it would be a problem to update email address X to become email
> address Y. I just don't see what you are getting at.
>
> For methods of recording the history of change Date, Darwen and
> Lorentzos have a book "Temporal Databases and the Relational Model",
> which discusses the issues and solutions at length.
>
> --