Answer:
Please check attachment.
Explanation:
Please check attachment. Book can be borrowed or not borrowed if not available. If not available book, request is registered and book is purchased. If book is bought then book can be borrowed. If request is cancelled then no problem or else book is assigned to the seeker(also he/she is informed) on availability. If book is available and assigned, then either book is returned within the deadline or returned after with fine or order is cancelled as its not needed anymore.