ActiveRecord 事务没有回滚整个事务

Question

我有一个票模型，用户可以从给定的序列号开始连续购买票。用户选择他们想要购买的门票数量，控制器生成该数量的门票并存储在数据库中。但是，如果一张票未能保存，则事务应该回滚，但在这种情况下不会。

tickets_controller.rb

...
def create
  number = params[:ticket_qty].to_i
  @tickets = Array.new
  number.times do |n|
    t = Ticket.new(ticket_params)
    t.serial_number = t.serial_number.to_i + n 
    @tickets.push(t)
  end

  respond_to do |format|
    ActiveRecord::Base.transaction do 
      @tickets.each do |t| 
        if t.save
          format.html { redirect_to tickets_path, notice: "#{number} #{"ticket".pluralize(number)} successfully created." }
          format.json { render :show, status: :created, location: tickets_path }
        else
          format.html { render :new, notice: "Some tickets have errors, check the serial number range" }
          format.json { render json: @ticket.errors, status: :unprocessable_entity }
        end
      end
    end
  end
end
...

重定向也是正确的，但没有出现任何通知。

Answer 1

要在出现错误时回滚您的事务，请将 t.save 替换为 t.save!

这将导致：

respond_to do |format|
  begin 
    ActiveRecord::Base.transaction do 
      @tickets.each &:save!
      format.html { redirect_to tickets_path, notice: "#{number} #{"ticket".pluralize(number)} successfully created." }
      format.json { render :show, status: :created, location: tickets_path }
    end
  rescue ActiveRecord::ActiveRecordError => e
    format.html { render :new, notice: "Some tickets have errors, check the serial number range" }
    format.json { render json: e.message, status: :unprocessable_entity }
  end
end

Answer 2

另一种选择是保存所有记录并根据结果手动触发回滚：

Ticket.transaction do 
  @save_results = @tickets.map(&:save)
  raise ActiveRecord::Rollback unless @save_results.all?
end

respond_to do |format|
  if @save_results.all?
    format.html # ...
    format.json # ...
  else
    format.html # ...
    format.json # ...
  end
end

您可以使用@save_results显示失败记录的数量：

"#{@save_results.count(false)} tickets have errors, ..."