Auto Enter County, State & Zip after entering City

Though townships may combine and use only one zipcode, there will always be only one USPS acceptable city for each Zipcode.  There are serveral sources for free zipcode databases.  The following is one example:

http://federalgovernmentzipcodes.us/

So when you build your tables you will want a table for Countries; States; Cities; Zipcodes and perhaps Counties.

Your Zipcodes table will reference the Cities table

In turn your Cities table will reference your States table

and again, in turn your States table will reference your Countries table.

So when you add a Zipcode to your addressee record, all the other related data will be available for display by using a query.

And though I agree with the gentlemen here about normalization, it may be a considerable necessity to store the individual components of your address in the addressee record: Country, State, City and Zip for the consideration of other countries where the address structure is quite different than that of the U.S..

These guys might have some other suggestions about foreign countries and how to manage them.  Best of luck.

Scott, what is the best way to go about correcting a database that breaks this normalization rule.   I have a contacts table that I enter the zip code and city (State is set to a default) for each record.  I see from this thread that my entering the city and zip code for each record is not the way it should be done.  

What's the best procedure for fixing this?

First, please don't piggyback your question on an older thread. Please use the Participate link to start a new thread. You can link to a previous thread if you think its applicable. 

Normalization has several levels. Generally, developers try to adhere to Third Normal Form (3NF). So, it is not necessarily bad to enter both city and zip. In fact, since some zip code span multiple cities, it may be cumbersome to use the Zipcode as a foreign key to determine City.

I generally do include City/State/Zip fields in my databases, though I may use lookup tables to autofill the info is I can. 

I really don't see anything to fix. If you want to discuss this further, please do so in a new question.

I know it is 5 years after Bob Larson posted his reply but when I try the link it is not working.  Does anyone have a new link for some sample fills or know of where I can more information on creating this process of adding the data from a query that has been created or using the unbound feature.

As I said, please don't piggyback onto an older thread. You can start a new thread and insert a link to the older thread.