A set is a collection of logically related tables, linked together so that you can search, report, and view data from component tables, as if they were a single table. Tables in a set are linked (or related) through a common field or expression. For example, you might use a set to create an invoicing system. Suppose you have two tables: one stores invoice information and the other stores customer information.
Since both tables are related through the Customer # field, referred to as a linking field, they can be joined into a set, allowing information to be viewed, entered, changed, and printed in both tables at the same time.