Question 9: (20 marks) (a) A college library needs to develop a program to manage the information about books, students, managers. Students borrow books from the library and return books back to the library. Managers buy book from the market and store to the library. A relational database is used to store this information. Before the coding, the database needs to be designed. Please use E-R diagrams to design E-R models of this information. You have to draw the entities including books, students and managers, and their relationship as well, list all attributes of the entities and their relationship, and point out their primary keys and mapping cardinalities. (10 marks) (b) Please use CREATE TABLE command to create all tables that you have designed above. You need to write the right SQL sentences, and a simple explanation in is also needed. (10 marks)