From: "D'Arcy" "J.M." Cain <darcy@druid.net>
To: michael.davis@prevuenet.com
Cc: pgsql-interfaces@postgreSQL.org
Subject: Re: [INTERFACES] [off-topic] Database normalization, can't be don e!
Date: Sat, 13 Mar 1999 08:57:15 -0500 (EST)
Message-ID: <m10Louh-0000buC@druid.net> (raw)
In-Reply-To: <93C04F1F5173D211A27900105AA8FCFC14527E@lambic.prevuenet.com>
Thus spake Michael Davis
> I copy the unit cost and unit price into the invoice. This makes sure the
> invoice does not change even though the inventory could change. May not be
> normalized but this is necessary. The invoice still references the
In fact, it is normalized. You just have to realize that things that
look similar and have the same name could still be different attributes.
In this case, you have two distinct attributes, the current, theoretical
price if you were to sell something and the actual price charged to a
client. Of course, these two are related in a conversational sense and
certainly one is derived from the other but item price is only one of
the components of invoice price. Another component (there could be
more such as client code, etc.) would be time.
In any case, ultimately your database should be designed to get the job
done, not to be the basis of a thesis on database design. I'm not
saying that you shouldn't worry about normalizing your database but
like many things it is important to understand the theory so that you know
when to break the rules. As long as you know what you are doing and it
is a conscious decision, a database schema could be 98% correct and
still be a good design. The test is, is it the best way to do the job.
--
D'Arcy J.M. Cain <darcy@{druid|vex}.net> | Democracy is three wolves
http://www.druid.net/darcy/ | and a sheep voting on
+1 416 424 2871 (DoD#0082) (eNTP) | what's for dinner.
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-interfaces@postgresql.org
Cc: darcy@druid.net, michael.davis@prevuenet.com
Subject: Re: [INTERFACES] [off-topic] Database normalization, can't be don e!
In-Reply-To: <m10Louh-0000buC@druid.net>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox