Re: How to normalize this?

From: Jan Hidders <hidders_at_gmail.com>
Date: Sun, 5 May 2013 10:10:49 +0200
Message-ID: <51861409$0$6057$e4fe514c_at_dreader36.news.xs4all.nl>


On 2013-05-04 23:32:18 +0000, compdb_at_hotmail.com said:

> On Thursday, May 2, 2013 6:23:07 AM UTC-7, Jan Hidders wrote:

>> But most> textbooks I know are correct and clear on this and will state 
>> that the> goal is for example a lossless-join and 
>> dependency-preserving> decomposition.

>
> Can you name some? Because I don't think books are clear about
> normalization within design, which involves generated predicates and
> constraint preservation. Normalization per se assumes the generated
> components are projections of the original, ie are suitably
> constrained, without addressing the management of those constraints (eg
> introducing FKs for lost FDs).
>
>> 1. Apply the 3NF normalization procedure we discussed earlier
>> 2. Include with each component only the FDs that generated that component

>
> It's not clear to me what you are describing or how it relates to
> arguing against stopping at 3nf.

I've described to you a normalization algorithm that seems to produce a schema in BCNF that is also lossless-join and dependency preserving, but also has no inter-component dependencies. That's not supposed to be possible according to the usual normalization explanation. So what went wrong here?

  • Jan Hidders
Received on Sun May 05 2013 - 10:10:49 CEST

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