/** CTRL+ALT+P to view **/

@startuml
hide circle

class Student {
  utclogin : text {key}
  mail : mail {key}
  surname : text
  firstname : text
}

class Api {
  code : integer {key}
  name : text
  year : year
  semester : H|E
}
note right of Api : (name,year,semester) key

Student "0..n" - "0..n" Api
(Student, Api) . Subscribe

class Subscribe {
  subdate : date
}

@enduml