Re: A Normalization Question
From: Jan Hidders <jan.hidders_at_REMOVETHIS.pandora.be>
Date: Mon, 12 Jul 2004 19:02:55 GMT
Message-Id: <pan.2004.07.12.19.03.20.22495_at_REMOVETHIS.pandora.be>
>
> The "standard" definition of redundanty you are referring to is a
> limited definition most applicable to a limited data model (RM).
>
> While all bet may be off in RM because anomaly only applies to fixed
> schema, such is not the case in my data model where even schema is
> considered just another thing.
Date: Mon, 12 Jul 2004 19:02:55 GMT
Message-Id: <pan.2004.07.12.19.03.20.22495_at_REMOVETHIS.pandora.be>
On Mon, 12 Jul 2004 10:01:31 -0700, Neo wrote:
>> > Because the three strings each represent the same thing, the string >> > 'brown', it is redundant. >> >> So you keep on claiming, but the standard definition of redundancy in >> normalization theory says otherwise.
>
> The "standard" definition of redundanty you are referring to is a
> limited definition most applicable to a limited data model (RM).
No. It's the general definition that is applicable to all data models, even such wild data models as XML.
>> > I realize the following are unusual examples, however a general data >> > model can't (application above it can) have prejudices as to what >> > updates are unusual. Suppose, the world is taken oven by Islam and >> > they desire every string in a computer to be spelled backwards, thus >> > 'brown' needs to be updated to 'nworb'. >> >> That means the schema is changing and then all bets are off because the >> notion of update anomaly is defined only with respect to a fixed >> schema.
>
> While all bet may be off in RM because anomaly only applies to fixed
> schema, such is not the case in my data model where even schema is
> considered just another thing.
No. Also there all bets are off because you have to redefine what exactly an update anomaly is and motivate that definition.
- Jan Hidders