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

Foreign keys provide the building blocks for relating tables. For example, in a customer order table, the salesperson field might contain an employee number.

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 ...