NYCPHP Meetup

[Daniel Krook]

> Normalization can have a huge impact on your apps -- it 
> can reduce many
> data entry errors and eliminate others entirely.  That is 
> its purpose. 
> Without normalization all of the time you spend supporting
> a slow app will
> be spent fixing errors in bad data.
> 
> But querying data is a different thing.  If you have known
> common queries
> that aggregate and join data, then by all means create 
> some summary system
> that is, hopefully, automatic and guaranteed to be right. 
> This is not
> really denormalization, though the relational theorist 
> will argue it is. 
> What it is in fact is the creation of derived tables based
> on normalized
> tables.
> 
> But anyway, normalize the tables users can directly modify, and use
> summaries derived from those normalized tables.  Then you 
> get accurate
> data coming in and that makes for accurate summaries.


Excellent point Kenneth,

This is the very thing Craig S. Mullins envisions in his "Death of 
Denormalization" articles. [1][2]   "With MQTs, you can achieve the best 
of both worlds: fully normalized tables to ensure data integrity during 
modification and MQTs for efficient querying." [2]   In essense, you don't 
have to change your data model just your hardware or software.

But Fabian Pascal says the solution isn't that denormalization will be 
rendered obsolete by faster physical resources, it's rethinking those 
software systems in the first place to support true high-form 
normalization that should eliminate performance issues.   "Hardware, 
product and optimization improvements are, of, course, always desirable 
and welcome, but they are only add-ons, not substitutes for the real and 
fundamental solution: well implemented TRDBMSs, whose performance is not 
hindered, but actually enhanced with fully normalized databases." [3].

Interesting reading, and nice affirmations to normalize. :)


[1] The Death of Denormalization
http://www.dbta.com/columnists/craig_mullins/dba_corner_0104.html

[2] Materialized Query Tables and the Death of Denormalization
http://www.zjournal.com/Article.asp?ArticleId=875

[3] Irrational Exuberance
http://www.dbazine.com/ofinterest/oi-articles/pascal18




Daniel Krook, Advisory IT Specialist 
Application Development, Production Services - Tools, ibm.com

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