I'm thinking of implementing a billing address model where the user has to fill in city, province, and country as address. However I also have a hierarchical table structure of one to many relationships already available to me where a county has many provinces and a province has many cities.(Although it's limited atm.) So basically if a user only provided a city ID i should be able to compute her province and country without needing to store them in the said model. but I don't know...
maybe later I will end up dumping the city-province-country tables because gathering and updating a full tree of such structure with correct info is a pain. besides I know of no other enterprise businesses that manage a complete tree of all inteational postal addresses accurate down to the customer's city. So I realized they mostly end up providing all these fields for the user to fill without validation with their policy being: "If you provide us with false address, you'll be the one in trouble."
With all that being said, I still see it as data duplication in my current structure to have the country and province columns in my model. What do you think is best to do in this regard?