Subtypes ‘Approved Reservation Request Part’ and ‘Ticket for Reservation’
BR 29 Tickets for a reservation request part can only be issued for an approved reservation request part.
Clearly, an approved reservation request part is a special kind of reservation request part. The Business Rule states that tickets can only be issued for such approved parts. The status of a reservation request part tells us which parts are approved, which is in a Fact Type played by the Supertype, so a Derivation Rule can be made that satisfies the requirement in . Because of BR 28 (see Section A3.2 below) the condition contains the three statuses ‘approved’, ‘assigned’ and ‘completed’. The tickets will still be for the same approved reservation ...