RE: Normalization

From: Mark Moynahan <Mark.Moynahan_at_apollogrp.edu>
Date: Thu, 29 Jul 2004 10:39:21 -0700
Message-ID: <73BB49215339D743903095833FFE4B17DA5097@apophxex4.apollogrp.edu>

Actually, I don't find it that odd. He's not stating that everything should be denormalized. He's just pointing out that there are times denormalization can be used.

Mark

-----Original Message-----

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Goulet, Dick
Sent: Thursday, July 29, 2004 10:26 AM
To: oracle-l_at_freelists.org
Subject: RE: Normalization

I find it very odd that the person who stated this did it. I have a = pile of respect for Don & find it rather impossible that he made this = type of statement. Guess we all have things to learn. Anyway, I = disagree with him, with the exception of a data warehouse. = Normalization is not to for the purpose of saving disk space, but so = that when something gets updated you have one and only one place to = update. If you want speed and normalization use Mineralized views & = query rewrite. That's what they were made for.

In a data warehouse the purpose is much different in that you want to =
preserve history. Therefore renormalizing the data is not just a way = around speed, but the way to preserve the history. Totally different = things altogether and speed or disk space has nothing to do with it.

Dick Goulet
Senior Oracle DBA
Oracle Certified 8i DBA

-----Original Message-----

From: Peter Robson [mailto:pgro_at_bgs.ac.uk] Sent: Thursday, July 29, 2004 11:51 AM
To: Paul Baumgartel
Subject: Re: Normalization

Outrageous! And this person TAUGHT???

In line...

PB> Q: What are the basic guidelines one should keep in mind while PB> designing a database? Is denormalization always good?

PB> A: I used to teach database design in graduate school, and your PB> question is excellent! The main purpose of high normalization was = the
PB> reduction of disk space, back when it mattered in the 1970s.

Absolute utter rubbish - doesn't understand what normalisation is. Doesn't understand what a 'data model' is.

PB> Today, I always introduce redundancy into the model whenever it can PB> eliminate an SQL join, but not always. I make my decision based on = two
PB> criteria:

PB> 1 - The size of the redundant item

PB> 2 - The volatility of the item (e.g. how often do I need to = duplicate
PB> updates)

Oh please - cannot cope with any more of this nonsense....

Hmmm, it might be interesting to know who it was - then perhaps ignorance is bliss...

peter
edinburgh

PB> =3D=3D=3D=3D=3D
PB> Paul Baumgartel
PB> Transcentive, Inc.
PB> www.transcentive.com


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Received on Thu Jul 29 2004 - 12:36:33 CDT