Re: Natural keys vs Aritficial Keys

On May 22, 9:10 pm, paul c <toledobythe..._at_oohay.ac> wrote:
> Bob Badour wrote:
> > paul c wrote:
>
> >> Bob Badour wrote:
>
> >>> paul c wrote:
>
> ...
> >>>> Oh, just remembered another one - fixed-point decimal arithmetic!
>
> >>> What do you need that for?
>
> >> To get the same answer as the lawyer with his amortization tables.
>
> > Integers are integers no matter the base.
>
> Sure they are, but I was talking about decimal points.  Eg., it bugs me
> that the most widely-used (that doesn't mean most popular) cpu
> 'architecture', Intel's, can't express the fraction 2/5 exactly.

If expressing exact rationals is what you want, then that is trivially done using integer arithmetic - as is fixed point decimal. Hardware decimals, which essentially died with the VAX, don't help you express rationals.

Have a play with these:
http://gmplib.org/ (see mpq for rationals) http://docs.sympy.org/

>  Maybe
> that fraction isn't too bad, can't remember the really awful ones at the
> moment.

Perhaps you are thinking of anything with a *binary* expansion longer than IEEE-754 can accommodate? http://brad.chalfan.net/binq/

>
> Now, here's another one:  Codd wrote his first database paper around
> 1969, forty years ago this year, where's the hardware support for
> relational algebra?

http://www.kickfire.com/blog/?p=177

> The steam engine revolution (no pun intended) made
> faster progress than that nearly three centuries ago.  I'll grant that
> the Future System/System 400 from IBM nibbled around the edges of db
> theory but never did distinguish physical from logical, sometimes I
> wonder whether Codd studied that while he was being paid to study IMS.
Received on Sat May 23 2009 - 05:22:06 CEST