Re: normalization
- From: Jared Still <jkstill@xxxxxxxxx>
- To: cstephens16@xxxxxxxxx
- Date: Tue, 1 Nov 2005 11:53:07 -0800
3rd normal form: attributes must depend ONLY on the the key attribute(s)
Calculated attributes violate that.
To preempt the question "What if the calculated column is calculated
from the PK attributes?": if that is the case, then questionable choices
were made for the key attributes.
Calculated fields are for reporting. eg. data marts and/or data warehouses.
--
Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist
On 11/1/05, Chris Stephens <cstephens16@xxxxxxxxx> wrote:
>
> There is a discussion going on at work concerning calculated fields.
>
> I am claiming that any calculated field in a table is a violation of
> at least 3NF if not 2NF. I can find all sorts of references on the
> web that justify my position but nothing that directly says this
> violates normalization rules.
>
> The person who i disagree with is claiming that 'technically',
> calculated fields do not violate 3NF. They are just not recommended.
> I am unable to find anything on the web coinciding with this argument.
>
> Anyone know of a site with a direct statement that calcualted fields
> violate 2NF/3NF?
>
> thanks,
> chris
> --
> //www.freelists.org/webpage/oracle-l
>
>
>
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