Boyce-Codd Normal Form (BCNF) differs from the 3NF only when there are more than one candidate keys and the keys are composite and overlapping. In case of Extra_Form it does not differ. Here is the conceptual schemas at each normal form:
Figure below shows the entity life history for Booking.
A Booking's life begins with a "Booking creation", and ends with a "Booking end". In between, its "Booking life" consists of some "Booking events".
In between an Booking's definition and its end, Booking is subject to series of "Booking events". The iterative nature of "Booking events" is shown by the asterisk (*) in the upper right corner of that event's box. The set of events constitute Booking's "Booking life": "Booking Form is filled", "Room Schedule is filled with booking details ", "Reservation Diary is filled with booking details" and "Deposit is taken".