Re: Design approaches about primary key

Daniel Morgan <damorgan_at_x.washington.edu> wrote in message news:<1070043650.390694_at_yasure>...
> Comment in-line.
>

<snip>
> > 3. Sometimes you have a problem whether you choose meaningful or
> > meaningless keys. If you had a table of countries a few years back, no
> > matter whether the primary key was a sequence or the United Nations country
> > code, when the Soviet Union split into multiple countries you had a problem.
>
> Not at all. It was easily handled. Records related to the USSR stopped
> having inserts and updates and new records were created for the new
> entities.
>
> This is no different from a wholesale-distribution environment where
> some customers go out of business and new customers are developed. There
> is no technological or business reason to treat them differently.

When working on a new design one thing that should be considered is any ANSI and ISO standards that may apply. In the case of countries there is an ISO country code. Conversion to using a standard then makes changes such as the break-up of the USSR back into the individual nations that made it up just a matter of inserting and perhaps updating a few rows as Daniel suggested.

Down the road use of these standards reduce future work necessary to exhcange data with international organizations.

Just another design consideration, as if getting accurate requirements isn't difficult enough.

• Mark D Powell --