Re: Relation Definition

"Frank Hamersley" <FrankHamersley_at_hotmail.com> wrote in message news:8E%Qd.164624$K7.145353_at_news-server.bigpond.net.au...
> "Dawn M. Wolthuis" wrote
<snip>
> This is not directed at you Dawn - but whatever happened to the KISS
> principle. Personally I usually suspect elaborate definitions (for a
> concept that would appear to me to be simple) as coming from high church
> adherents. My two bob's worth. Frank

Yes, agreed. I started laughing as I went in search of the full definition of the term "relation" from Date's latest book, and I figured if I did not type it all in, then others would not be able to appreciate it in the same way. (apologies to Date whose precision I often truly do appreciate)

What I contributed to the dictionary a while back as the defininition of relation was what I thought a relation to be:

"1. A relation is a subset of the set of ordered tuples (A1, A2, ... Am) formed by the Cartesian cross-product of sets S1 x ... x Sm where each An is an element of Sn."

Someone else contributed the note below it in the glossary and then mAsterdam simply put a "2..." for the definition that I'm trying to find now -- the one employed by database folks. Given that many on this list consider themselves from the relational theory school, it sure seems it would be helpful to know what we mean when we use the term "relation". I know what I mean by it (above), but then Alfredo and others attack, so I've been on a search for one I can work with.

If others don't like Date's definition either, then what precise definition of relation works for you? Thanks a bunch! --dawn Received on Thu Feb 17 2005 - 14:20:48 CET