title: Howto Design "hierarchical data" for a Learning Management System(LMS)
body: <p>I'm supposed to design a Learning Management System (LMS), from scratch.
  In regards to the "Course" entity, I have 3 levels of info (Course, Topic, Sub_Topic). Imagine it like a tree.
  Now, which of these methods (or any better way?) is more useful?</p>
  
  <p>1- Using "Adjacency List Model" (http://www.sqlsummit.com/AdjacencyList.htm) or </p>
  
  <p>2- using 3 Tables , each for one of these levels, and join them for getting records? </p>
  
  <p>Please bear in mind that each of these levels have "separate attributes" and have connections with "Quizes" as well. So there are some interaction among each of these fields with "Quiz entity" as well ..  </p>
  
  <p>P.S. System will be implemented in Django and MySQL ..</p>