Re: two nasty schemata, union types and surrogate keys

From: Walter Mitty <wamitty_at_verizon.net>
Date: Sat, 26 Sep 2009 15:55:50 GMT
Message-ID: <aQqvm.3367$Jd7.3034_at_nwrddc02.gnilink.net>


"paul c" <toledobythesea_at_oohay.ac> wrote in message news:hIcvm.46588$PH1.27780_at_edtnps82...
> Sampo Syreeni wrote:
>> Still, to return to my original point, what do y'all think about the
>> encoding of facts such as "yes, there are two separate persons called
>> John Smith, and no, we don't have any more information about them as
>> persons, yet given their sets of cars owned, the one with a Ferrari
>> and the one with a Lamborghini are two different persons"?
>> ...
>
> Since all I usually care about is theory, it's fine by me. But I might
> feel differently if my name were John Smith and would probably switch to a
> different repair shop.

Believe it or not, I once ran into a building wide phone directory where looking up the name "John Smith" gave me the extension of the wrong person named "John Smith". In order to find the one I was looking for, I had to look up under "Jack Smith". The designers had used the name (actually the last name comma first name) of the person as the primary key of an indexed file. And this was at a computer company!   Received on Sat Sep 26 2009 - 10:55:50 CDT

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