# Re: A simple notation, again

Date: Tue, 17 Jul 2007 01:10:59 -0700

Message-ID: <1184659859.447753.106610_at_i38g2000prf.googlegroups.com>

On Jul 16, 7:05 pm, "Brian Selzer" <br..._at_selzer-software.com> wrote:

> "David Cressey" <cresse..._at_verizon.net> wrote in message

*>
**> news:o4Lmi.4051$fj5.2089_at_trnddc08...
**>
**> > Using the notation [A B C] for <NOT> (A <AND> B <AND> C), etc.
**>
**> > The following [ A [B]] means "A implies B" for Boolean algebra. What
**> > is
**> > the corresponding thing for Relational Algebra?
**>
**> > Also, I'm trying to come up with a bracket notation for a "literal
**> > relation", like literals for simple datatypes like numbers and character
**> > strings.
**>
**> > I'm toying with this:
**>
**> > [["David" "Cressey" 1]
**> > ["Marshall" "Spight" 2]
**> > ["Bob" "Badour" 3]
**> > ["Jan" Hidders" 4]]
**>
**> How about something like this
**> {(Last, First, Num) :
**> ("David", "Cressey", 1),
**> ("Marshall", "Spight", 2),
**> ("Bob", "Badour", 3),
**> ("Jan", "Hidders", 4)}
*

You imply order (adjacency) when relation attributes should not be
subjected to any....
Received on Tue Jul 17 2007 - 10:10:59 CEST