Re: FK relations...

Internet Coop wrote:
>
> Sure let me do a little better job of explaining..
>
> Three tables:
> Person
> car
> Car Parts
>
> Primary Keys
> Person:
> SSN
>
> CAR:(Information about a persons car)
> SSN
> VIN number
>
> Car Parts:
> SSN
> Vin number
> part number
>

 <snip>

Couldn't the tables be set up like this? Person:
Person-id meaningless number, assigned via sequence SSN CAR:
Person-id
VIN number

Car Parts:
Person-id
Vin number
part number

Maybe that's not feasible in your case.
In general I try to use sequence values for any attribute used to uniquely identify a real-world object, especially is this attribute will be present in many tables. (e.g. in the three tables above perhaps it would be better to have a sequence instead of using VIN number in two tables)
Of course there would probably be an index on SSN in the person table.

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