当我注释掉我的after_save回电时，我的 ActiveRecord 关联工作得很好。在 Rails 控制台中，您会看到：
> @report = Report.create :name => "foo"
=> #<Report id: 9, name: "foo", created_at: "2013-03-05 09:51:55", updated_at: "2013-03-05 09:51:55">
> @question = @report.questions.create :description => "bar"
=> #<Question id: 18, standard_id: nil, description: "bar", element_id: nil, condition_id: nil, blueprint_name: nil, blueprint_url: nil, created_at: "2013-03-05 09:52:32", updated_at: "2013-03-05 09:52:32", additive: false, instructions: nil>
> @report.questions
=> [#<Question id: 18, standard_id: nil, description: "bar", element_id: nil, condition_id: nil, blueprint_name: nil, blueprint_url: nil, created_at: "2013-03-05 09:52:32", updated_at: "2013-03-05 09:52:32", additive: false, instructions: nil>]
> @question.reports
=> [#<Report id: 9, name: "foo", created_at: "2013-03-05 09:51:55", updated_at: "2013-03-05 09:51:55">]
但是，当我将以下after_save回调添加到时，关联停止工作question.rb：
def create_matching_surveys
self.reports.each do |report|
report.reviews.each do |review|
review.competitors.each do |competitor|
competitor.surveys.find_or_create_by_question_id(self.id)
end
end
end
end
然后，在 Rails 控制台中，您将获得：
> @report = Report.create :name => "foo"
=> #<Report id: 13, name: "foo", created_at: "2013-03-05 10:20:51", updated_at: "2013-03-05 10:20:51">
> @question = @report.questions.create :description => "bar"
=> #<Question id: 24, standard_id: nil, description: "bar", element_id: nil, condition_id: nil, blueprint_name: nil, blueprint_url: nil, created_at: "2013-03-05 10:21:02", updated_at: "2013-03-05 10:21:02", additive: false, instructions: nil>
> @report.questions
=> [#<Question id: 24, standard_id: nil, description: "bar", element_id: nil, condition_id: nil, blueprint_name: nil, blueprint_url: nil, created_at: "2013-03-05 10:21:02", updated_at: "2013-03-05 10:21:02", additive: false, instructions: nil>]
> @question.reports
=> []
无论报告是否包含有竞争对手的评论，都会发生这种情况。
奇怪的是我认为回调是在问题被保存后发生的？所以按照权利，协会也应该在这一切发生之前保存，对吧？
我如何解决它？
更新
我想我必须在对象生命周期的正确位置调用回调，但我找不到那个位置。这就是我认为的原因：
> @report = Report.create :name => "foo"
=> #<Report id: 20, name: "foo", created_at: "2013-03-05 12:29:35", updated_at: "2013-03-05 12:29:35">
> @question = @report.questions.create :description => "bar"
=> #<Question id: 31, standard_id: nil, description: "bar", element_id: nil, condition_id: nil, blueprint_name: nil, blueprint_url: nil, created_at: "2013-03-05 12:30:14", updated_at: "2013-03-05 12:30:14", additive: false, instructions: nil>
> @question.reports
=> []
> @question.update_attributes :description => "foo"
=> true
> @question.reports
=> [#<Report id: 20, name: "foo", created_at: "2013-03-05 12:29:35", updated_at: "2013-03-05 12:29:35">]
顺便说一句，该方法现在在 question_observer.rb 中：
class QuestionObserver < ActiveRecord::Observer
def after_save(model)
model.reload
model.reports.reload
model.reports.each do |report|
report.reviews.each do |review|
review.competitors.each do |competitor|
competitor.surveys.find_or_create_by_question_id(model.id)
end
end
end
return true
end
end