Re: By The Dawn's Normal Light

From: erk <>
Date: 27 Oct 2004 10:40:19 -0700
Message-ID: <>

> Functions are even more powerful -- you know you have a unique
primary key
> that, effectively, maps to the remainder of the data for that, uh,
> I'm not sure what the current view of that is with relations, but I
> that each relation must have one or more (sets of) candidate keys.
In that
> case, we can view them as functions as well, choosing one of the
> key sets as the "from" and the remainder of the attributes as the

I'd say functions are less powerful, compared with the relational operators. Although functions are simpler, they're a subset of binary relations. I think mapping a key value to "the rest of the data" gives you fewer options - you can't express exactly what it is you want.

But of course a lot of this hinges on the terms "power" and "simple"... - erk Received on Wed Oct 27 2004 - 19:40:19 CEST

Original text of this message