Re: Alternate keys.

<snip>
> That's a circulat argument. First you say to make a PK based on
> custname,custaddr, productord, etc, Then you say "Better introduce a
> number".,but based on your original objecttion that OrderNo is not an
> appropriate PK, Gee, I'm dizzy!

Well, the subject was alternate keys... The name, birthdate, etc, etc is what would
be designed (analysis time), the number would be the technical implementation.
So the number is / becomes the PK, leaving the name, etc stuff as *alternate*
primary key - it still identifies that one record, just as the number would!
> > >
> > > > BTW: customer would be a better example: people never refer to,
 or are
> > > > referred to by numbers, always by name.
> > >
> > > What if you have two customers with the same name?
 You start getting the picture: see answer to Niall
> > >
> Yes. The picture I get is that OrderNo would be OK.
>
> > > Sanrenkur
> > >
> > >
> > > Sent via Deja.com http://www.deja.com/
> > > Before you buy.
> >
> >
>
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.
Received on Tue Oct 24 2000 - 06:42:08 CDT