Re: Primary Key

Joshua D. Drake wrote:
> In "theory" the item that would be a natural key in this instance is
> the VIN. You would of course have to make some kind of allowance for
> cars that don't have a VIN (nothing in the last what... 50 years?).
And some kind of allowance for Title 49, Sec. 565.4, subsection (d):

"The VINs of any two vehicles manufactured within a 30-year period shall
not be identical."

After 30 years, all bets are off. And the manufacturers have been
tinkering with the VIN due to the inadequacies of the VIN number. Since
VINs were first standardized in 1980, does this mean we are approaching
a Y2010 problem?

I'm sure someone has defined a "vehicle", but I don't know what number
applies when you've pieced together a rebuilt engine, salvaged
transmission, junkyard hood and so-on to get a working car. I think
custom builders end up applying for a new VIN but I don't think that
applies to repairs. Of course defining when a vehicle becomes a
different vehicle is a problem that remains regardless of choice of key.

VINs are apparently not required on directly imported vehicles (ie.
those imported by other than the manufacturer).

The above applies to the US. I'm sure the laws of other countries vary.

Cheers,
Steve