Heath Normal Form

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SanDroid

Posted Monday, November 14, 2011 7:40 AM

Ten Centuries

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First let me say interesting question.
I had heard about this in the 80's but had really dropped it along with cars that run on water and the gushot from the grassy knoll uuntiltoday.

Thank you for the reeducation commrad.
BTW: Love the profile picture.

Post #1205147

SanDroid

Posted Monday, November 14, 2011 7:58 AM

Ten Centuries

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L' Eomot Inversé (11/13/2011)

bitbucket-25253 (11/12/2011)

Without prior knowledge of the QOD author I surmised it was you...

Now a general question for yourself .... in your experiences, around the world, what would you say are the percentage of DBs in 4NF and / or higher (5NF,6NF).

Well, I would guess about 50%, or maybe a bit lower, are in 4NF or higher.

actual counts from experience:
In 2007: system with 9 databases, 7 in 4NF or higher, 1 in 2NF (denormalised Management Information database), 1 not even in 1NF (arrogant and incompetent people who wouldn't follow instructions).
In 2002: system with 3 databases, 1 in BCNF and 2 not even in 1NF.
in 2000: system with 2 DBs, both in 4NF or higher.
Before 2000: most everything 4NF or higher, except MI stuff....

IMHO: I have yet to find a database that comes with any current business software that is fully normalized to 4NF in every physical data structure. After a quick rundown of what is in my current production environment many of them fail simply becuase they store duplicate denormalized historical data in the transactional database for reporting and auditing. We can talk all day long about how this could be done better, faster, stronger.
I wonder how many of us have got anyone to agree to a massive budget needed to fully normalize.

For some reason large scale business applications (like JDE and others) have many decission makers in bussiness believing that any database using under 10 gigabytes of data storage is small and running on systems way bellow Midrange.
Cool

Post #1205160

OzYbOi d(-_-)b

Posted Monday, November 14, 2011 8:41 AM

Ten Centuries

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Thanks for the question Tom. Smile

Post #1205221

L' Eomot Inversé

Posted Monday, November 14, 2011 9:43 AM

SSCertifiable

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SanDroid (11/14/2011)

Actually I would expect historical data held for reporting to be denormalised, but I would also expect it to be in a separate MI database (I'm a dinosaur - I haven't learnt to type BI instead of MI). But the stuff for audit should be the stuff that was generated in real time by the real transaction so quite separate from reporting data.

I wonder how many of us have got anyone to agree to a massive budget needed to fully normalize.

Once a system that should be normalised has been built unnormalised, no one has budget to do proper normalisation until shortly after the brown stuff meets the blades.

Tom
Que conclure à la fin de tous mes longs propos? C'est que les préjugés sont la raison des sots. (Voltaire, 1756)

Post #1205342