A mini$-$university library system keeps track of books, authors, publishers, and copies of the book in that

library. Each book can be written by one or more authors, and each author can write multiple books. Books

are published by a publisher. A book has a title, ISBN $($unique$),$ and a publication year. An author has their

name and ID$.$ Publishers have a name and an ID as well. A book copy has a copy number $($unique for one

book but NOT among multiple books$),$ condition, and availability in the library.