Hello again,

I have a table (session_comments) with the following fields structure:

student_id (foreign key to students table)
session_id (foreign key to sessions table)
session_subject_ID (foreign key to session_subjects table)
user_id (foreign key to users table)
comment_date_time
comment

Now, the combination of student_id, session_id, and session_subject_id will uniquely identify a comment about that student for that session subject.

Given that combined they are unique, even though they are foreign keys, is there an advantage to me making them the combined primary key for that table?

Thanks again.