A 6NF also exists, but its purpose is not to remove redundancy and it is therefore only adopted by a few data warehouses, where it can be useful to make tables irreducible.
In the absence of any rules restricting the valid possible combinations of traveling salesman, brand, and product type, the three-attribute table above is necessary in order to model the situation correctly.
Suppose, however, that the following rule applies: A traveling salesman has certain brands and certain product types in their repertoire.
Suppose that Jack Schneider starts selling Robusto's products breadboxes and vacuum cleaners.
With the new setup we need to add only a single entry (