I'm in the process of designing a database to contain regional data to be used inside a CRM system.
So, a user suspects that things like the city or country are automatically filled (or maybe just suggested) when he types in certain pieces of information.
Now my question: Is this feasible when using international schemes? Is it possible to get a mapping between PostalCode -> City -> Country in Germany, like I can do in the US or Japan?
How to design such a database with normalization? I already found offers like GeoNames is doing, but they're not normalized let alone referenced via FK constraints.