Question

我想检查数据库中是否存在数据..如果不是我应该保存数据..我用过吗？控制器中的方法如下..

 def party_order_create
   @party_order = PartyOrder.new(party_order_params)
   if not PartyOrder.exists?(@party_order)
   then @party_order.save
     flash[:notice] = "Party Saved Successfully!!!"
     redirect_to :action => "party_order_index"
   else
     flash.now[:notice] = "Party not Saved"
     render "party_order_new"
   end
 end

它不起作用..请帮我纠正..

Answer 1

尝试使用

if @party_order.present?

而不是：

if PartyOrder.exists?(@party_order)

所以它可以改写为：

def party_order_create
   @party_order=PartyOrder.new(party_order_params)
   @party_order.save
   if @party_order.present? 
     flash[:notice] = "Party Saved Successfully!!!"
     redirect_to :action => "party_order_index"
   else
     flash.now[:notice] = "Party not Saved"
     render "party_order_new"
   end
 end

Answer 2

@party_order=PartyOrder.find_or_create_by(party_order_params)

if @party_order.present?

  // code

else

  // code

end

//或试试这个

@party_order=PartyOrder.where(party_order_params)

if @party_order.present?

    flash.now[:notice] = "Party not Saved"

    render "party_order_new"

else

    @party_order=PartyOrder.new(party_order_params)

    if @party_order.save

        flash[:notice] = "Party Saved Successfully!!!"
        redirect_to :action => "party_order_index"
    end

end

存在？方法无法在rails中工作

2 个答案: