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Re: Lucid statement of the MV vs RM position?

From: JOG <jog_at_cs.nott.ac.uk>
Date: 27 Apr 2006 10:51:21 -0700
Message-ID: <1146160281.894837.300310@j33g2000cwa.googlegroups.com>


David Cressey wrote:
<snippage>
> Some people in this forum argue that "NULL" has
> no counterpart in mathematics, so it shouldn't be part of the model. That
> misses the point. If you are building a DATA model, you have to address
> the question: what are you going to do when the data isn't there? as well
> as the question, how do you prevent missing data? That is why Codd
> addresses the issue of missing data, rather than evading the issue.
</snippage>

I could not disagree more. There is a reason there is no counterpart in mathematics - the "null concept" is not necessary. Why then is it suddenly necessary in a data model based upon mathematics? Because "missing data" is viewed incorrectly by most participants, as though it is some obtuse construct external to the underlying theory. This is absolutely not the case - _everything_ one could possible say about missing or unknown data can still happily be described in terms of predicate logic. It is not a 'hole' in the data, it is different data.

Back to the MV... Received on Thu Apr 27 2006 - 12:51:21 CDT

Original text of this message

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