so why not just import the data?
have a table which defines the area codes
do a join on the area code to that table to pull in what ever data you associate with the code (use a left join)
the main probelm I can see is how do you handle area codes that are not defiend.. do you rejet the import, or do you make sure your link is non RI.. ie the source data/ chld table can have a code which you dont have in the code table. run a query after the import is donw to find waht codes if any are not defined and update those codes..
becuase somebody somewhere will create a new code, somebody will miss type a code, somebiody will forget a code.