ActiveRecord:如何克隆嵌套关联?

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我目前正在克隆这样的单级关联:

I'm currently cloning a single-level association like this:

class Survey < ActiveRecord::Base def duplicate new_template = self.clone new_template.questions << self.questions.collect { |question| question.clone } new_template.save end end

这样就可以克隆Survey，然后克隆与该调查相关的Questions.美好的.效果很好.

So that clones the Survey then clones the Questions associated with that survey. Fine. That works quite well.

但我遇到的问题是每个问题has_many Answers.所以Survey has_many Questions which has_many Answers.

But what I'm having trouble with is that each question has_many Answers. So Survey has_many Questions which has_many Answers.

我不知道如何正确克隆答案.我试过这个:

I can't figure out how to clone the answers properly. I've tried this:

def duplicate new_template = self.clone self.questions.each do |question| new_question = question.clone new_question.save question.answers.each do |answer| new_answer = answer.clone new_answer.save new_question.answers << answer end new_template.questions << question end new_template.save end

但这会产生一些奇怪的东西，实际上是替换原始答案然后创建新答案，因此 ID 无法正确匹配.

But that does some weird stuff with actually replacing the original answers then creating new ones, so ID's stop matching correctly.

推荐答案

使用 deep_clonable gem

new_survey = original_survey.clone :include => [:questions => :answers]