Re: A Normalization Question
Date: Tue, 6 Jul 2004 14:19:11 -0400
Message-ID: <2l08nkF7122uU1_at_uni-berlin.de>
"Neo" <neo55592_at_hotmail.com> wrote in message
news:4b45d3ad.0407060943.79e8c638_at_posting.google.com...
> > > With respect to dbs, normalization is the process of eliminating or
> > > replacing duplicate things with a reference to the original thing
> > > being represented. Within the context of a db, duplicate references
> > > are not considered redundant because they are unrelated to the thing
> > > being represented.
> >
> > Redundancy (and Normalization!!!) in the RD world is based exclusively
> > on Functional Dependencies.
>
> RM is a limited data model. That RM's concept of
> redundancy/normalization is only based on functional dependencies, may
> be the reason why RM's fails to see 'brown', 'brown', 'brown' as
> redundant.
Yes, it has limitations, but normalizing data is not one of them. The RM defines normalization. You just refuse to accept normalization as it is because you will owe someone $1000.
>
> > Here is a reference for _you_: "Fundamentals of Database Systems",
Elmasri &
> > Navathe, Third Ed. pages 476-495. They start with functional
dependencies
> > and explain to you how (and when and why) to get all the way to 5NF and
all
> > points in between. In only 20 pages!
>
> Unfortunately 5NF does not cover everthing.
I never said it did.
A better reference is C.J.
> Date "An Intro to Database Systems", 6th Ed, Chapter 10, Further
> Normalization I: 1NF, 2NF, 3NF, because he states on pg 291 "By now
> the reader might well be wondering whether there is any end to this
> progression and whether there might be a 6NF, a 7NF, and so on ad
> infintum...We content ourselves with the rather equivocal statement
> that there are indeed additional normal forms ..."
How does that make it better? It's a contention, not a proven fact. Anyway, how would you know it is better since you never read Navathe?
>Normalizing
> 'brown', 'brown', 'brown' is higher than 5NF.
Even if it is, that doesn't make it better- it just makes it different. Received on Tue Jul 06 2004 - 20:19:11 CEST