A television set has a unique serial number and is associated with a specific manufacturer and a model for that manufacturer. Each television set is associated with exactly 1 manufacturer and 1 model for that manufacturer. A manufacturer has a unique name. A manufacturer can produce 1 to many television models. A model does not have a unique name but is associated with at least 1 manufacturer. An electronic store has a unique name and a unique address that consists of a street number, street address, town, state and zip code. A store stocks 1 to many television sets but a television set can only be found at 1 and only 1 store