FUNCTION calc_term_gpa (curr_s_id NUMBER, curr_term_id NUMBER) 
	RETURN NUMBER
	IS
  CURSOR credits_cursor IS
    SELECT s_id, credits, grade
    FROM enrollment, course_section, course
    WHERE enrollment.c_sec_id = course_section.c_sec_id
    AND course_section.course_id = course.course_id
    AND s_id = curr_s_id
    AND term_id = curr_term_id
    AND grade IS NOT NULL;
  credits_row credits_cursor%ROWTYPE;
  total_credits NUMBER(3);
  grade_points NUMBER(1);
  grade_credit_points NUMBER(3);
  total_credit_points NUMBER(3);
  student_gpa NUMBER := 0;
BEGIN
	total_credit_points := 0;
  total_credits := 0;
  FOR credits_row IN credits_cursor LOOP
	 IF credits_row.grade = 'A' THEN
     grade_points := 4;
   ELSIF credits_row.grade = 'B' THEN
     grade_points := 3;
   ELSIF credits_row.grade = 'C' THEN
     grade_points := 2;
   ELSIF credits_row.grade = 'D' THEN
     grade_points := 1;
   ELSE
     grade_points := 0;
   END IF;
 grade_credit_points := grade_points * credits_row.credits;
 total_credit_points := total_credit_points + grade_credit_points;
 total_credits := total_credits + credits_row.credits;
 END LOOP;
 student_gpa := total_credit_points/total_credits; 
 RETURN student_gpa;
EXCEPTION
	WHEN zero_divide THEN
		student_gpa := 0;
		RETURN student_gpa;
END;