A University wants to develop a student course registration system. We got the following descriptions

by prospective users.

For every student we store information about his$/$her Student$\_$ID$,$ name, address and Major. Every

student in the system has a single major. For every Major we store its Major $\_$Code and its name.

Courses are identified by their Course$\_$ Code but we also keep information about their names. A course

can have several admissible majors, or the list of admissible majors can be empty. In the latter case, any

major is admitted into the course. Semesters are identified by their Semester $\_$Code. We store

information about the registrations of the students to courses in different semesters. Information about

a student is recorded in the system only if he$/$she has registered to a course. For every registration of a

student to a course we also store the grade of the student to this course if it is available. Otherwise we

store a null value.

Draw an E$/$R diagram for the Student Registration System assuming that the entity types $($weak or

regular$)$ are STUDENT, SEMESTER, COURSE, and MAJOR. Specify $($a$)$ keys, $($b$)$ structural constraints, and

$($C$)$ roles $($if this is necessary$).$ For the constraints use both the traditional notation $($single$/$double lines

and numbers across the diamonds$)$ and the $($ min,max $)$ notation. State clearly any additional

assumptions that you made in designing the ER diagram.