Re: atomic

"Bob Badour" <bbadour_at_pei.sympatico.ca> wrote in message news:472fd42f$0$14860$9a566e8b_at_news.aliant.net...
> paul c wrote:
>> I think it would have 20!
>
> r1:
>
> Name Car
> ----------- ------------
> {bill} {car1,car2,car4}
> {john,fred} {car3}
>
>
> r2:
>
> Car Colour
> ---------------- ---------
> {car1,car3,car4} {red}
> {car2} {green}
>
>
> r1 join ( r2 rename Car as Vehicle ):
>
> Name Car Vehicle Colour
> ------------- ------------------ ----------------- ---------------
> {bill} {car1,car2,car4) {car1,car3,car4} {red}
> {bill} {car1,car2,car4) {car2} {green}
> {john,fred} {car3} {car1,car3,car4} {red}
> {john,fred} {car3} {car2} {green}
>
> I count 4 rows.

I have been on the fence about RVAs for years. I can see why Date and others (including you guys) want to talk about them for the purpose of understanding where the theory takes you. But this little exchange shows me that I never want to see RVAs implemented in any product. (I am not talking about paul's confusion about the relations in question.)

I don't care if there is a problem that can be solved only with RVAs, the misery they would invite just wouldn't be worth it. The old joke says if we ever teach computers to understand English we will find out that programmers can't write it. If we ever produce a product that supports RVAs we will find out programmers are wanting in that area too.

Roy Received on Tue Nov 06 2007 - 11:39:37 CET