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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Normalization
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 [mailto:jreyes_at_dazasoftware.com]
Sent: Thursday, July 29, 2004 10:48 AM
To: oracle-l_at_freelists.org
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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