Create a database trigger for the following situations:
(a) The price of all double rooms must be greater than £100.
(b) The price of double rooms must be greater than the price of the highest single room.
(c) A booking cannot be for a hotel room that is already booked for any of the specified dates.
(d) A guest cannot make two bookings with overlapping dates.
(e) Maintain an audit table with the names and addresses of all guests who make bookings for hotels in London (do not store duplicate guest details).