我该如何查看new_record？关联保存在rails中

Question

我很抱歉，但我如何检查保存的关联是否为new_record？因为在保存关联后调用了after_save或before_save。

class Children
   belongs_to parent
   after_create :check_new_record_of_parent
   # before_save :check_parent_saved   # call this method also not work

   private 
   def check_new_record_of_parent
     parent.new_record?   # not work because parent is saved before this method called
   end

   def check_parent_saved
      parent.nil? 0 : 1
   end
end

class Parent
    has_many children
end

我调用children.update_attributes（nested_form）而不是children.save;

Answer 1

def before_save
  @was_a_new_record = new_record?
  return true
end

def after_save
 if @was_a_new_record
   ...
 end
end

试试这个，看看它是否有效。