Paul,

I think that you are 'over-thinking' the problem. The number of
possible postal codes in really not that significant.

Remember, not all letters/number combinations are used -- heck, there
are only 12 primary (first char) postal code areas. Also, large rural
sections of the country are 'covered' by a single postal code. It is
only in urban areas where fine level of detail/variation can be found in
the postal code themselves.

So to have to re-link the postal codes for a change in the postal zones
would not require a large amount of processing.

You could do this in an SP, which would process through the postal codes
and test for each possible postal zone. In the absolute worse case, the
SP would need to perform 6 selects/tests for each postal code (although,
I think you could do it in 1 select). Given that the zone table would
be very small, it would be cached in server memory -- thus have a very
limited I/O overhead.


Sean Leyne
Toronto, Ontario, Canada