Re: Rookie asks about "Normalization"

roywagner_at_aol.com (Roy Wagner) wrote:
>>a completely normalized app.would be Ideal but is not always the best
>>
> This is an absolutely true statement.
>
>In very simiple terms, a normalized database contains no redundant
>information. Any repeated information is pointed to using, usually an
>number that is the primary key of the table containing that type of
>information (once and only once).

This is just partially true. It is not always a number, more often is a composite key. Adding a numeric, unique identifier (AKA Surrogate Key) is already a denormalization.  

 It is indeed true that normalization is very good in an ideal world but real world problems could cause you to move away from it. It is important that this happens in a controlled way, i.e. knowing the denormalization that is applied. It is also true that modern databases mechanisms, like triggers, help a lot to enforce data integrity even whendenormalization is present.

 Just my opinion ...

  Renato Brazioli

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