title: Why 1:M and not N:M (ER diagram)
body: <p>I found this from here  <a href="https://www.tutorialcup.com/dbms/object-based-data-models.htm" rel="nofollow noreferrer">https://www.tutorialcup.com/dbms/object-based-data-models.htm</a></p>
  
  <p><a href="https://i.stack.imgur.com/lHQ2H.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/lHQ2H.png" alt="enter image description here"></a></p>
  
  <p>and I try to understand why the type of mapping between Student and Lecturer is 1 to many. So, I have a question...</p>
  
  <p>Why the mapping is 1:M and not N:M? As the diagram represented, I can understand that one student can be tough by many teachers but one teacher can teach at most one student </p>