rails 3 validation on uniqueness on multiple attributes

Question

I use Rails 3.0.0.beta4

I want to add a validation on uniqueness on two attributes, that means that my model is valid if the couple of \'recorded_at\' a

Answer 1

Multiple Scope Parameters:

class TeacherSchedule < ActiveRecord::Base
  validates_uniqueness_of :teacher_id, :scope => [:semester_id, :class_id]
end

http://apidock.com/rails/ActiveRecord/Validations/ClassMethods/validates_uniqueness_of

This should answer Greg's question.