Why Use This Schema?
Associating a student with a class is the logical idea behind registering for a class, so Students & Classes corresponds to a real phenomenon -- a plus
Having classes listed in the student record violates the goal of a fixed length record, and makes it cumbersome to create a class list -- minuses
Having students listed in the class record violates the fixed length record goal, and makes it cumbersome to create a registration list for each student -- minus
“Registering students” -- what STAR does -- can be done without touching either Students or Classes tables -- a plus