Standard schemas

Are there any sites with 'standard schemas' for certain, repetitive database needs? For example, addresses and their components. Does anyone have a schema for addresses that will work for the USA *AND* internation addresses? entities ---------- Countries States Counties Cities street addresess. Postal Codes Some rules: ------------- A/ Do duplicate countries B/ No duplicate states in Countries (states seem only to exist in 'Federal' governments) C/ No duplicate postal codes in Countries D/ Duplicate cities are allowed in Countries, and in the world. E/ Duplicate cities are allowed in States. F/ Cities can have multiple postal codes G/ Postal codes are assigned to only one city. H/ Postal codes are assigned to counties. I/