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Re: Counting propositions

From: Tony <andrewst_at_onetel.net.uk>
Date: 17 Jun 2004 13:13:15 -0700
Message-ID: <c0e3f26e.0406171213.73e101f7@posting.google.com>


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> > > > > > > > > > > Ok. But why there is a need to know this number ?
> > > > > > > > > > > It is like saying "today I made 100 affirmations".
> > > > > > > > > >
> > > > > > > > > > Have you never wanted to know how many of something you
> had?
> > > Can
> > > you
> > > > > > > > > > not envisage a large business wanting to know, for
> example,
> > > how
> > > many
> > > > > > > > > > employees it has?
> > > > > > > > >
> > > > > > > > > Employees yes. Propositions no.
> > > > > > > >
> > > > > > > > Very droll ;-)
> > > > > > > >
> > > > > > > > But the fact is that from the N propositions we have that say
> "We
> have
> > > > > > > > an employee named xxx with salary yyy ...", we can deduce the
> useful
> > > > > > > > fact that we have N employees - simply by counting the
> propositions.
> > > > > > >
> > > > > > > What made you so sure.
> > > > > >
> > > > > > What makes you so unsure? Are you making some kind of
> philosophical
> > > > > > point that I'm not getting?
> > > > >
> > > > > Well, because you don't directly count employees, but you count
> propositions
> > > > > about employees instead, it is a legitimate question to ask if the
> result is
> > > > > accurate and why.
> > > > >
> > > > > Other reasons:
> > > > > - the database may contain propositions about past, current and
> future
> > > > > employees
> > > > > - the database may contain propositions about employees in different
> > > > > relations (or relvars)
> > > > > - it might be hard to distinguish propositions about employees from
> other
> > > > > propositons in the database
> > > >
> > > > Well, you ceertainly have to know what the propositions mean before
> > > > you can get a meaningful answer by counting them. If the propositions
> > > > include past and future employees then you should ensure that you only
> > > > count the propositions about current employees by adding the
> > > > appropriate WHERE clause.
> > > >
> > > > It shouldn't be at all hard to distinguish propositions about
> > > > employess from other propositions in the database, because a
> > > > relation/table must only hold propositions of one type.
> > >
> > > So you say that the employees are in *one-to-one correspondence* with
> the
> > > propositions about employees, or something like that and this is the
> reason
> > > you can count propositions to determine the number of employees ?
>
> > I do, though I sense I may be walking into a trap ...
>
> :-)
>
> > I guess the term "external predicate" comes in here, i.e. the
> > knowledge that these propositions EACH ??? assert the employment of 1
> > employee is implicit.
>
> You see, there are propositions that assert the employment and propositions
> that assert other things about the employee.

Yes - like a table of employee_salary_history may assert 7 facts about 1 employee. But I know that, because an employee is identified by Emp_id (or whatever), and this table of propositions is not.

> > From that, one can deduce that the existence of
> > N propositions implies the existence of N employees.
>
> Not true. There might be more propositions per employee (without
> duplicates).

Not in the table of propositions that has Emp_ID as the key there can't be.

> Why do you insist in counting the propositions, for counting the employees
> then ?

Because it works? ;-) Received on Thu Jun 17 2004 - 15:13:15 CDT

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