Design the tables for a library

A university library needs a database. The facts:

• Readers (students and staff) borrow books.
• The library often owns several copies of one title and must know exactly which copy is at whose home.
• A book can have several authors and an author can have several books.
• For every loan the library needs to know when the book was borrowed, when it is due and when it was returned.

Design the tables: for each one give its name, primary key and foreign keys. Explain how you handle the relationship between books and authors and why a loan refers to the thing you attached it to.