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Re: Beginner help needed in database design

From: Frank van Bortel <>
Date: Thu, 03 Feb 2005 12:52:49 +0100
Message-ID: <ctt37g$51p$>

Drago Ganic wrote:

> Frank,
> You  and I are entities (something, object .. whatever term You prefer). As 
> such, we have properties (features, attributes, fields, ...) which

>>>describe<< us . The whole set of the properties >>identify<< us from other
>>>entities in the Universe. Identification is equivalent to uniqueness,
>>>because You (and I) believe that we are unique and have at least ONE
>>>property which value is different. In we are described with the same set
>>>of properties (but different values) we belong to the same Entity Type (or
>>>Class ... name it). This is also a shortcut, because it's easier to group
>>>the individual entities in sets/types. You and I are in the same set :-)
> Yes, the ID numbers are a TECHNICAL shortcut because the number of 
> properties is infinite and we never know them all explicitly  .. but we do 
> know (or believe to know) that we are unique. Therefore we need an 
> identification vehicle. People "names" were a nice try to solve the problem. 
> If we lived in a small village with 200 people and with no communication 
> that would be OK. Today, numbers (integers) are used. In 10 or so years 
> fingerprints or eyescans will be used (for entities which have them, of 
> course  :-).
> So, YES the IDs are a technical thing in so far as NAMES ("Drago Ganic", or 
> "Frank van Bortel") are a technical because we do not now the values of all 
> the attributes. In that case (If we would know everything about anybody) the 
> "natural" key would be it's attribute-value set. In the absence of that 
> knowledge, we add (or invent) an attribute which we call Name, Surname, 
> Name+ Surname, SSN etc.
> In the discourse above I have not mention Microsoft, Oracle, IBM, SQL, Java, 
> Basic, pointers, indexes, hash tables etc. So it is and it is not Technology 
> :-)
> Greetings from Croatia
> Drago Ganic
> "Frank van Bortel" <> wrote in message 
> news:ctrh1m$f6s$

>>Mark A wrote:
>>>"Frank van Bortel" <> wrote in message
>>>>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
>>>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
>>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

Guess we are in agreement, then.
Frank van Bortel
Received on Thu Feb 03 2005 - 05:52:49 CST

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