For this question, refer to the diagram shown in Figure 1. This diagram represents what a Universitys course enrollment database might look like. A university can have several departments, each of which can have a number of courses, such as CMPT 355. Some of these courses have multiple sections. These sections can be of different types, such as a lecture, lab, or tutorial. Assume that a section can only exist in one term and that each section has only one instructor. Multiple students can be enrolled in multiple sections.

(a) (2 points) On the Students table, aside from id, what is a candidate key?

(b) (2 points) If we didnt use a surrogate key as the primary key on the Enrollments table, what candidate key could you select as the natural primary key and why?

(c) (2 points) For the Sections table shown, what columns are foreign keys?

(d) (4 points) How is the Sections table related to Enrollments, Courses, Instructors, and Terms? Describe these relationships in terms of 1:1, 1:n, n:1, and n:n. i. How is Section related to Enrollments? ii. How is Section related to Courses? iii. How is Section related to Instructors?

iv. How is Section related to Terms?

Students id int student number int first_name varchar(100) Courses varchar(100) Departments last_name email_address varchar(100) int id int major_code varchar(10) code Enrollments code varchar(10) varchar(10) varchar(100) gender char(1) name name varchar(100) id course_desc text student_id int Sections course_units numeric section_id int int department_id int grade numeric section_code varchar(10) status_code varchar(10) Instructors course_id int id int lec_type varchar(10) employee_number int term_id first_name varchar(100) max_enrollment last_name varchar(100) num_enrolled Terms seniority_date date num_waitlisted id int email_address varchar(100) instructor_id code varchar(10) days varchar(3) name varchar(50) start_time time start_date date end_time time end_date date location_code varchar(10) Figure 1: A data model that represents a University enrollment system