3.a. Design a simple database schema with 4 or less files for a University database system indicating all applicable constraints and information. In this. University, students have majors and take courses which they receive grades for. These grades are used to compute the student grade point average, at any point in time. As the database designer, you shauld decide the necessary attributes for students and courses. Also, show a sample database state for the database. b. Using your database, describe the differences between logical and physical data independence