Find all students (StudIds) who had taken a course from each professor in the MUS department.

Write the query of Exercise 5.20 using TRC and DRC.

One way to write this query is to ?rst de?ne a view, MUSprof, which contains all tuples from Professor that correspond to Musics Department. Then we could use the quanti?er ?P ? MUSprof to express this query similarly to the use of the view CSProf at the end of Section 13.1. The solution below uses the implication instead of the view.

a. TRC:



{S.StudId | Student(S) AND

       ?P ? Professor(P.Dept= ’MUS’ ?

                 ?R ? Transcript ?T ? Teaching

                 (S.Id = R.StudId AND P.Id = T.ProfId AND

                  T.CrsCode = R.CrsCode AND T.Semester = R.Semester )) }

DRC:



{StudId |?Name?Addr?Status Student(StudId, Name, Addr, Status) AND

        ?ProfId?ProfName(Professor(ProfId, ProfName, ’MUS’) ?

                 ?CrsCode?Sem?Grade(Transcript(StudId, CrsCode, Sem, Grade)

                 AND Teaching(ProfId, CrsCode, Sem))) }