Re: Newbie question about db normalization theory: redundant keys OK?

From: raylopez99 <>
Date: Fri, 14 Dec 2007 11:43:05 -0800 (PST)
Message-ID: <>

On Dec 14, 9:36 am, David Portas
<> 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.
> --

Don't feel obligated to answer in any way, but if you recommend a single book for somebody who is coding for fun but has a science background that gets into this theory please feel free to state so--if it's Date et al let me know.

Also perhaps (and I'm just literally reading this stuff for the first time, I absolutely no clue otherwise) the changing of a primary compound key is a problem because if you change the key, and it's at the top root of a tree of relationships, then the cascades and triggers that are affected by changing the primary key are so extensive that as a practical matter, for a *** Terabit dB, then you'll have to spend a week of maintanence downtime to have the new primary key "perculate through" the database (just a thought).

RL Received on Fri Dec 14 2007 - 20:43:05 CET

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