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Re: Beginner help needed in database design

From: Frank van Bortel <>
Date: Wed, 02 Feb 2005 22:36:22 +0100
Message-ID: <ctrh1m$f6s$>

Mark A wrote:
> "Frank van Bortel" <> wrote in message
> news:ctqf0h$2ln$

>>SSN is a prime example is a technical key. Why is
>>it people do not have a problem recognizing me by name,
>>but computers do?
>>Frank van Bortel

> That is not true. Names are not unique (maybe yours is). For most people,
> there is another person somewhere with the same exact name. Not true with
> social security name or employee number (at least it is intended that these
> are unique).

Even when I was called John Doe (which is a common name in the US of A, I believe), people know me. The name may not be enough, but the features of my face, along with the name certainly do.
And if that's too hard to understand/program for computers and uniquely identify me, how about my birth date, my father's and mother's names, and their birth dates? Or the fact I write to this ng, and have been doing that for about 10 years now?

Chances are smaller than the number of people on this planet, that is not unique.

But - it is not compact; in the times memory was scarce it surely would not have been acceptable. So, take a number. Nice and easy, small, and guaranteed to be unique on top of it all. And we call it: number.
And as this particular number was invented by the (US) Social Service, let's call it a Social Security Number.

I don't have one, but I live in a country with a civilized social security system :^) I've other numbers attached to me...

But that is what a technical key is: a meaningless number (BTW: is SSN really meaningless, or is it coded?), instead of (mostly many) fields, together making up a unique identifier.

Frank van Bortel
Received on Wed Feb 02 2005 - 15:36:22 CST

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