In a school setting, a student has a unique ID$,$ name, address, and major. The school offers several courses, each is identified by a unique ID and has a title. Each student can register for many courses but may not register for any. Also, each course can be taken by many students, but some courses may not have any enrollments. Courses are taught by an instructor. Each instructor has a unique ID$,$ name, address, and location. An instructor can teach many courses but may not teach any. Each course is taught by one and only one instructor. For each student taking a specific course, the school wants to track the grade, semester, and year student $$ that is the grade received on each course, and when the course was taken.