Write the Relational Algebra (RA), Tuple Relational Calculus (TRC), and Domain Relational Calculus (DRC) whichever is labelled against the question. Note that some of these queries might not be expressible in Relational Algebra, QBE, or Relational Calculus. Note that some of these queries might not be expressible in Relational Algebra, QBE, or Relational Calculus. For such queries, informally explain why they cannot be expressed.

Students(snum, sname, major, standing, age, gpa)

Faculty(fid, fname, deptid)

Courses(cnum, cname, course_level, credits)

Offerings(onum, cnum, day, starttime, endtime, room, max_occupancy, fid)

Enrolled(snum, onum) PLEASE ANSWER THE FOLLOWING QUESTIONS :

6. (RA,DRC) Find students with a GPA > 3.0 that are taking exactly two courses.

7. (TRC, QBE) Find courses taught by only one faculty member.