Re: Table Design Question

From: Zach Wells (no_zwells_spam_at_ain1.com)
Date: 04/28/04 

Date: Wed, 28 Apr 2004 10:59:50 -0400

Anith Sen wrote:

> Zach,
>
>
>>>An email address is a horrible candidate as a primary key. <<
>
>
> There are no universal rules regarding how a specific attribute fits as a
> primary key at the logical level. It exclusively depends on the business
> model (conceptual schema) which is being represented in a database.
>
> The only formal & general considerations for a primary key in relational
> databases are stability, simplicity, familiarity & minimality.
>

You're missing the point I'm trying to make. The whole thread started
over the age-old discussion of using natural primary keys vs using
generic keys. Joe (and I assume others) seem to take the stance that
there is never a reason in a "properly" designed database to need a
generic key. I say there is and as an example I use a VERY common type
of data, a Person. I'm asking the question: What is a good, valid,
natural key for people? Email is not one. It may be in some very
specific cases but it definitely is not a good key in general. Neither
is SSN. I'm claiming that there really isn't a good natural key that you
can use as a primary key when dealing with people and that using a
generic key is not only acceptable, but required.

Zach

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