campus note

campus note

Note 1.

Single Table Inheritance 
http://api.rubyonrails.org/classes/ActiveRecord/Base.html

class Teacher < User
  has_many :courses
end

class Course 
  belongs_to :teacher
  has_and_belongs_to_many :students
end

class Student < User
  has_and_belongs_to_many :courses
end

Table Structure
<1. users, should have a type column to trigger single-table inheritance.
<2. courses, for Teacher and Course, 1 to many, :foreign_key => teacher_id
<3. courses_students, for Course and Student, many to many, :foreign_key => student_id