Re: Normalization by Composing, not just Decomposing

From: Jan Hidders <>
Date: Fri, 09 Apr 2004 17:36:38 GMT
Message-ID: <GaBdc.65712$>

mAsterdam wrote:
> Anyway, the irreducible normal form (one non-key attribute only)
> was recently mentioned again by Chris Date as the 6th normal form.

Are you sure? Date's 6NF is a special normal form for when you have temporal data. It's not uncontroversial, by the way.

> AFAIK it (irreducible normal form - by another name) first popped up in
> NIAM (when it was called Nijssen's Information Analysis Method, late
> 1970's, after one of its originators, prof Nijssen. Now the N stand for
> Natural) - I don't remember what is was called in that context -
> something like 'elementary sentence'.

I believe the term to be "elementary facts". Actually finding out what the elementary facts are is essentially the same as normalizing to 5NF.

  NIAM is mentioned at the ORM site
> Jan Hidders kindly referred us to,, so maybe I can
> find the origins there.

To a large extent ORM *is* NIAM.

  • Jan Hidders
Received on Fri Apr 09 2004 - 19:36:38 CEST

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