I'm struggling with a way to look at "pre-requisites" as a relationship between a Student table and a class rooster. Essentially, I'm trying find who those students that have not taken a pre-req clas

[Horacio]

I'm struggling with a way to look at "pre-requisites" as a relationship between a Student table and a class rooster. Essentially, I'm trying find who those students that have not taken a pre-req class but who are currently enrolled in the course

The student table has the PK set as STUD_ID and the Class-roster table has the STUD_ID as well as the CLASS_ID but I'm stymied on how to set up a relationship that shows only those students who have not taken the prereq. Lost... any pointers accepted!