search for: students_school

...ents_assignment has_many :students_class, :dependent => :destroy has_many :classes, :through => :students_class has_many :students_extracurricular_activity, :dependent => :destroy has_many :extracurricular_activities, :through => :students_extracurricular_activity has_many :students_school, :dependent => :destroy has_many :students_schools, :through => :students_school end Suppose a student can''t belong to a class and extracurricular activity that occur at the same time? I figure that this validation would be best handled in the Student class since the other case...