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

In Rails 2, I would have written:

validates_uniqueness_of :zipcode, :scope => :recorded_at

In Rails 3:

validates :zipcode, :uniqueness => {:scope => :recorded_at}

For multiple attributes:

validates :zipcode, :uniqueness => {:scope => [:recorded_at, :something_else]}

Answer 2

Dont work for me, need to put scope in plural

validates_uniqueness_of :teacher_id, :scopes => [:semester_id, :class_id]

Answer 3

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.