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 - 03:10:59 CDT
