U.S. and Canadian Postal Code (ZIPcode) validation for the IBM i

"What do IBM i users do for Postal Code and ZIP code validation of
transactions on the i?

Do you have a recommendation on a U.S. and Canadian Postal Code
(ZIPcode) database for the IBM i?
Other than Worksright.com?

Last year we purchased from ZipInfo.com a database of U.S. and Canadian
Postal Codes (ZIP codes) for less than $200.
It was a simple text file in comma-separated value format with almost a
million rows.
Uploaded it to our IBM i into DB2 and created a table.
Added additional columns for data of interest to Ameristar (our sales
rep names, etc.)

Now we want to refresh our database with the latest corrections and
updates from the U.S. postal service and Canada.
As I consider the challenge of updating our custom database file with
additions/deletions/changes provided by ZipInfo.com in .CSV format, I
ask myself,

"What do other IBM i customers do for Postal Code and ZIP code
validation?
How do you keep your ZIP code database current and up-to-date?
Eric Lehti