I think the best way to do this is to have a zip code table with fields for zip code, city and state. Then you create a relationship from your zip code field to that in the zip code table. Using this relationship, you can create lookups (or auto-entered calculations) for each of the city and state fields so that when a zip code is entered, they auto-fill.
The only issue you may run across is where two cities have the same zip code. Will that ever happen?
Actually that is fairly common. As an example, I am from Gloucester, MA which has a zipcode of 01930, however different parts of Gloucester are known as Magnolia, East Gloucester, Lanesville etc...
In most cases I would think Gloucester would be acceptable but if you need to distingish between sub-divisions, why not create a drop-down list of cities based on the same zipcode relationship and assign it to the city lookup field.
Once you have entered a zipcode, select the city drop-down to see if there are multiple selections and if so select the appropriate choice.
I answer questions on various forums. I use Google.
A Google Search for "zipcode filemaker"
responds with a list of links including several that I have used in the past.
There is also a Custom Google Search for Filemaker...
A search here for "zipcode" yields
thanks for that search tip David...really helpful.
it brought up this site:
which has a free database of city/state/zip which you can link and then do lookup with
DO NOT use the above zip codes link!!!!!
i think it might have had something to do with my whole db file crashing irretreviably.