Re: help with normalization

From: mAsterdam <mAsterdam_at_vrijdag.org>
Date: Sat, 03 Sep 2005 19:51:16 +0200
Message-ID: <4319e229$0$11073$e4fe514c@news.xs4all.nl>

Jon Heggland wrote:
> mAsterdam says...

>>Tonkuma wrote:
>>
>>>I think that you shoud consider to add forein keys and constraints,
>>>before consider normalization.
>>
>>Some constraints, yes, but not foreign keys.
>>Foreign keys are a result of the normalization steps.

>
> Foreign keys have very little to do with normalisation. What you first
> and foremost need to do is to determine the functional dependencies.
> Without those, I don't see how it is possible to normalise in any
> systematic and formal manner.

Except (obviously) for the first sentence I agree. First you should get the meaning (including the FDs) right.

A quote from Date's intro (8th ed, p 356):

"FDs are a semantic notion ... (in fact, they are part of the relvar predicate). Recognizing the FDs is part of the process of understanding what the data /means/ ... " Received on Sat Sep 03 2005 - 12:51:16 CDT