user
- - - - - - - - - - - - - - -
id last_activity
500 8:00PM
100 7:00PM
200 2:00PM
institution
- - - - - - - - - - - - - - -
user_id name
500 Harvard Institution
instructor
- - - - - - - - - - - - - - -
user_id job_title fname lname
100 Dr. Alex Adam
student
- - - - - - - - - - …