Re: Treating addresses in 3NF?

>> You mean to tell me that a prestigious, highly efficient
organisation like the British Royal Mail does not provide everyone with a fully normalised relational model ... <<

For 'UK postcode databases', the Royal Mail holds the copyright and will licence you an 'outwards' database (i.e. the first segment of the full postcode) for about 150 UK pounds a year, or an 'inwards' database (i.e. the full 9- or 10-character postcode) for about 500 UK pounds per year.

The U.S. zipcodes are nested geographical areas of the form abbbcc-ddee. The first digit is a multi-state region, the next three are part of a state, the next two are postal districts within a city or county.

Sometimes a zipcode belongs to a single entity, like a hospital, government agency office, university, etc.

The stuff after the dash are trickier:

1. The first two "zip+4" digits are the postal carrier route and the last two are neighborhoods within the route. The idea is to phsyical sort the mail for easy delivery.
2. If the zipcode is a post office, the last four digits are all or part of a box number.

zip -> city
zip -> state
(zip, zip+4) ->> (street, city, state) Received on Sat Nov 16 2002 - 20:40:19 CST