Re: design

From: Daniel Morgan <dmorgan_at_exesolutions.com>
Date: Fri, 20 Sep 2002 21:23:38 GMT
Message-ID: <3D8B91D4.67A0D7D2@exesolutions.com>

just_learning wrote:

> Hi all, not sure if I'm in the correct group for this one, but I'm a newbie,
> ...wonder if someone can help me out with a very specific question about
> creating an ERD.I'm not even as far as implementation, just conceptual
> entities and attributes etc.
>
> I have an ERD which has an entity called Concessions
> and subentities called food, ride and game. I would like to track price
> and/or revenue, but I'm unsure of how to do it without a calculated field...
> I can send the ERD if more clarity is needed..
> please help!
> Thanks in advance!
> J_L

It is generally a very bad design that stored calculated values. Calculations should be done on-the-fly when selecting from the database. The exception is when on-the-fly calculations cause performance issues.

Daniel Morgan Received on Fri Sep 20 2002 - 16:23:38 CDT