Re: Relational Algebra

"Zubair" <zubairusman_at_yahoo.com> wrote in message news:3fa7c45d$0$12704$fa0fcedb_at_lovejoy.zen.co.uk...
> I'm not sure if this is the right place to post this but could someone
help
> me out with some relational algebra.
>
> I have three tables
>
> Student(Student#, sname, saddress, dob, degreetype)
> Course(Course#,cname, syllabus, day, time)
> Attendance(Student#,Course#, Year)
>
> I need to represent the following query in Relational Algebra
>
> SELECT sname
> FROM Student, Course, Attendance
> WHERE Student.Student# = Attendance.Student# AND
> Course.Course# = Attendance.Course# AND
> Course.cname = "DB" AND
> Student.degreetpe = "PP"

Consider each of the clauses separately. What operation or function does the SELECT clause represent? What operation or function does the FROM clause represent? What operation or function does the WHERE clause represent? Can one simplify the result by combining any of the operations or functions to derive another operation or function? Received on Tue Nov 04 2003 - 16:59:09 CET