The superiority of surrogate versus natural keys is a hotly debated topic among database developers. Susan Harkins offers some insights into when -- and why -- you might choose one over the other.

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

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, ...