Common example is the Customers table with a SalePeople subclass table that both use the EmployeeID as their primary key)<BR><BR>When I make a foreign key reference to these tables in other tables ...

A primary key is a field used to uniquely identify every record in the database. Sometime primary keys are obvious, for example a car license plate could be used to uniquely identify cars. Often ...

For National 5 Computing Science, revise the use of primary and foreign keys and the difference between flat file and relational databases.