Re: Proposal: 6NF
Date: Wed, 04 Oct 2006 13:22:03 GMT
Message-ID: <%zOUg.8386$GR.2556_at_newssvr29.news.prodigy.net>
"JOG" <jog_at_cs.nott.ac.uk> wrote in message
news:1159954091.119164.155490_at_m73g2000cwd.googlegroups.com...
> All of your points represent a wild goose chase in my eyes Brian. A
> proposition with a NULL in it is no proposition at all. From a logical
> perspective, case closed. A relation tuple with a NULL in it is no
> relation tuple at all. From a mathematical perspective, case closed.
> Trying to invoke the 'kludge perspective' is hardly going to convince a
> theoretical newsgroup.
>
Is the empty set a value? Yes, it is. So why can't a null be?
By your reasoning, a proposition with an integer in it is no proposition at
all; a proposition with a string in it is no proposition at all; a
proposition with a widgit in it is no proposition at all.
Also, haven't you heard of the existential quantifier? For example, if a
EXISTS x (P(x) XOR Q(x))
where P is defined in terms of X and Y and where Q is defined in terms of X, Y, and Z is a perfectly valid construct in FOPL. Received on Wed Oct 04 2006 - 15:22:03 CEST