class UpdateMemoMessageTime < ActiveRecord::Migration def up memo_count = Memo.all.count / 30 + 1 transaction do for i in 1 ... memo_count do i MemoMessage.page(i).per(30).each do |memo_message| if memo_message.memo if memo_message.memo.respond_to?("created_at") memo_message.created_at = memo_message.memo.created_at elsif memo_message.memo.respond_to?("created_on") memo_message.created_at = memo_message.memo.created_on end memo_message.save puts memo_message.id memo_messages = MessageAll.where("message_type = '#{memo_message.class.to_s}' and message_id = '#{memo_message.id}'").first memo_messages.created_at = memo_message.created_at memo_messages.save end end end end end def down end end