为未命名为“:id"的数据库设置主键；

我正在使用:rails 2.3.5 ruby​​ 1.8.7 和 Windows 7 Home Basic

I am using: rails 2.3.5 ruby 1.8.7 and Windows 7 Home Basic

我得到了一个数据库并将其连接到 rails，从中读取和获取数据没有问题.现在我想做的是在其中添加一些功能(添加、编辑和删除)，但是当我尝试通过执行以下代码将主键设置为表的主键 (ProductCode) 时:

I was given a database and I connected it to rails, having no problems reading and getting data from it. Now what I want to do is add some functionality in it (add, edit and delete) but when I try to set my primary key to the table's primary key (ProductCode) by doing this code:

class Product < ActiveRecord::Base
self.primary_key :ProductCode
end

我在执行 @products = Product.find(:all, :limit => 10) 时遇到此错误:

I got this error when doing a @products = Product.find(:all, :limit => 10):

PosController#index 中的参数错误参数个数错误(1 代表 0)

ArgumentError in PosController#index wrong number of arguments (1 for 0)

我该如何解决这个问题?

How can I solve this ?

这是我的控制器代码:

    class PosController < ApplicationController

    def index
        @cards = Card.find(:all)
        @products = Product.find(:all, :limit => 10)
    end

    def new
        @pro = Product.new
    end

    def edit
    @pro = Product.find(params[:id])
    end

    def update
    @pro = Product.find(params[:id])
    if session[:user_id]
                @log = "Welcome Administrator!"
                @logout="logout"
            else
                @log = "Admin Log in"
                @logout=""
            end

    respond_to do |format|
      if @pro.update_attributes(params[:product])
        flash[:notice] = 'product was successfully updated.'
        format.html { redirect_to(:controller => "pos", :action => "index") }
        format.xml  { head :ok }
      else
        format.html { render :action => "edit" }
        format.xml  { render :xml => @pro.errors, :status => :unprocessable_entity }
      end
    end
  end

    def create
    @pro = Product.new(params[:product])

    respond_to do |format|
      if @pro.save
        flash[:notice] = 'product was successfully created.'
        format.html {redirect_to (:controller => "pos", :action => "index")}
        #format.xml  { render :xml => @product, :status => :created, :location => @product }
      else
        format.html { render :controller => "pos",:action => "new" }
        #format.xml  { render :xml => @product.errors, :status => :unprocessable_entity }
      end
    end
  end

  def destroy
    @pro = Product.find(params[:id])
    @pro.destroy

    respond_to do |format|
    flash[:notice] = 'product was successfully deleted.'
      format.html { redirect_to(:controller => "pos", :action => "index") }
      format.xml  { head :ok }
    end
  end
end