Re: Plural or singular table names

"Paul Vernon" <paul.vernon_at_ukk.ibmm.comm> wrote in message news:bj4f8q$l0i$1_at_gazette.almaden.ibm.com...
> "Bob Badour" <bbadour_at_golden.net> wrote in message
> news:my65b.384$652.40534048_at_mantis.golden.net...
> > "Paul Vernon" <paul.vernon_at_ukk.ibmm.comm> wrote in message
> > news:bj2mh2$fri$1_at_gazette.almaden.ibm.com...
> > > BTW Could you show me how a constraint alters the meaning of a set
> > > of tuples? For me, a constraint alters the allowable set of
meanings, it
> > > does not alter the meaning of a particular set of tuples.
> >
> > Constraints identify the meaningful set of possible statements.
> >
> > Consider the following relation:
>
> Relation variable or relation value?

After I posted my other response, I thought of a way to drive the point home. See below:

> > F:
> >
> > X Y Z
> > = = =
> > 2 2 4
> >
> > Do the following constraints give F different meanings?
> >
> > Z = X + Y
> > Z = X * Y
> > Z = X ^ Y
>
> If F is a variable then yes, if it is a value then no.

Consider two scenarios. In the first, F above is a variable. In the second, G below is a variable.

G:

X Y
= =
2 2

In the second scenario, F is a value derived from G using one of the constraint expressions above making the expression part of the predicate of F and constraining the values that can appear in F.

Do you see how the different constraints give F different meanings? Received on Wed Sep 03 2003 - 16:08:02 CEST