Re: Normalization

From: Juan Carlos Reyes Pacheco <jreyes_at_dazasoftware.com>
Date: Thu, 29 Jul 2004 11:47:38 -0400
Message-Id: <41091C1A.000001.01220@CACHITOSS>

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.

Please see the official ORACLE-L FAQ: http://www.orafaq.com

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Received on Thu Jul 29 2004 - 10:50:11 CDT