SQL

The following relations are used to store data about students, courses, enrollment of students in courses and teachers of courses. Attributes for primary key in each relation are marked by ‘*’.

 Students (rollno*, sname, saddr)
 courses (cno*, cname)
 enroll(rollno*, cno*,grade)
 teach(tno*,tname,cao*) 

(cno is course number, cname is course name, tno is teacher number, tname is teacher name, sname is student name, etc.)

For the relational database given above, the following functional dependencies hold:

 rollno → sname,sdaddr      cno → cname
 tno → tname rollno,             cno → grade 

(a) Is the database in 3^rd normal form (3NF)?
(b) If yes, prove that it is in 3 NF. If not, normalize, the relations so that they
are in 3 NF (without proving).