Re: normalisation
Date: Sat, 27 Apr 2002 15:02:42 GMT
Message-ID: <3ccabc10.7119046_at_news.ch.kpnqwest.net>
On Sat, 27 Apr 2002 14:47:57 GMT, "Chris" <c_at_coelle.net> wrote:
>You got me there......but I just don't know if I am doing it right.
Well, we all have to learn ... and experience is often the best
teacher. As to normalization rules, there is often a choice as to how
to set things up. Often it is even necessary to de-normalize a design
for the sake of performance. However, one should always try to
normalize as thoroughly as possible, then only de-normalize when
performance dictates.
I suggest reading "SQL for Smarties" by Joe Celko; also, John Viescas
has written "SQL Queries for Mere Mortals" which gives a good
introduction to normalization. For more in-depth coverage, try Chris
Date's "An Introduction to Database Systems".
Having second thoughts about the rental rate, you will need to store
this information because it is an unchangeable part of the contract
between the client and the rental company, even if it is dependent on
several other factors.
If you remove car_type and amount_due from the table, you should be
OK. Good luck.
Bob Hairgrove
>Unfournatly no one really helps you at uni and all my mates have the same
>problems.....
>It's very hard when you never have done it before
>
rhairgroveNoSpam_at_Pleasebigfoot.com
Received on Sat Apr 27 2002 - 17:02:42 CEST