不能选择DB计数导轨

Question

我是Ruby和Ruby on Rails上的新手，所以我想知道，为什么此代码不起作用！（我来自php：//）。

    class SayController < ApplicationController
  def hello
        # function for user data
        if ( params[:username] != nil && params[:password] != nil )
            if ( params[:username].length > 3 && params[:password].length > 3 )
                @err = 0
            else
                @err = 1
            end
            if ( @err == 1 )
                @messege = "Hey, yor username Must be longer that 3 charasters."
            else
                @messege = "Ok, We will check your user data"
                result = Users.count( :username => params[:username], :password => params[:password] )
                    if ( result == 1 )
                        @l = "Hey, #{params[:username]}."
                     else
                        @l = "Users data was wrong."
                     end 
            end
        else
            @messege = "Please fill in the text fields."
        end
  end
  def goodbye
  end
end

和错误：

 ArgumentError in SayController#hello

未知键：用户名

rails.root：/home/home/cdr/perku应用程序跟踪|框架跟踪|完整的跟踪

app/controllers/say_controller.rb：17：in`hello'

请求

参数：

{"用户名" =>" asdasdasdasdaaaasdfda"， "密码" =>" [过滤]}

显示会话转储

显示ENV转储响应

标题：

无

Answer 1

  result = Users.where("username = ? and password = ?",
     params[:username], params[:password] ).count