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RE: Normalization

From: Bob Lofstrand <>
Date: Thu, 29 Jul 2004 11:06:23 -0500
Message-ID: <>

I have to disagree. With materialized views I see no reason at all to denormalize. Keep the base tables fully normalized and speed your queries by pre-joining into materialize views. Correctness and speed. The only price is disk space and that is a small price to pay to avoid inconsistant data.

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

From: Juan Carlos Reyes Pacheco [] Sent: Thursday, July 29, 2004 10:48 AM
Subject: Re: Normalization

Hi Paul
I am not an expert, but yes trying to become "expert".

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

In simple words.
The reason to normalize is don't duplicate data fooly The reason to denormalize is don't get you boss kick your ass, because a query is taking too much time.

There is a limit when tuning, when you can't get more performance, unless you denormalize, buy hardware or move to RAC.

The guideline is performance, and common sense. If denormalizating it takes 0,03 s and without denormalizating takes 2s without taking in count that it increase 10x the amount of block read, etc. ..and this is a process t hat run 1000's of time a day, don't denormalizing is a mistake.
..but if this process is run few times a day, denormalizing is a mistake.

4th and 5th normalization is not always advisable, all depends.

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Received on Thu Jul 29 2004 - 11:01:10 CDT

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