A car salesman would like to track the cars sold to his customers. A car can only have one owner. Someone can only be considered a customer when they have been sold a car. A customer additionally has an address file that the sales man would like to keep separate from the customer file. A customer can only have one address and an address file can only be related to one customer. Cars have chassis number, make, model and year. Customers have a TRN, name and address such as street, city, parish, zip code and country.

How many foreign keys will be required for the implementation of the file structure?

database