嵌套模型的Rails验证

Question

I'm using Rails 3.2 and 4.

I have a Survey and I want to validate that each question has between 2 and 5 answers. Survey has_many Questions, Questions has_many Answers and belongs to Survey. Answer belongs to Question.

How would I do this?

Answer 1

In Question model

validate :answer_count


def answer_count
  self.errors[:base] << "Can have answers only between 2 and 5" if answers.length<1 || answers.length>5
end