保存对象到DB

Question

我有一个模型：

class Scr < ActiveRecord::Base 
    def self.find_scrs 
    find(:all, :order => "id") 
    end 
end 

视图（形式）：

<div class="scr-form"> 
<fieldset> 
    <% form_for :scr, :url => { :action => :save_scr } do |form| %> 
    <p> 
    <label for="scr_id">Id:</label> 
    <%= form.text_field :id, :size => 40 %> 
    </p> 
    <p> 
    <label for="scr_description">Description:</label> 
    <%= form.text_area :description, :rows => 3, :cols => 40 %> 
    </p> 

    <%= submit_tag "Save", :class => "submit" %> 
    <% end %> 
</fieldset> 
</div> 

和控制器：

class InboxController < ApplicationController 
    def index 
    @scrs = Scr.find_scrs 
end 

def add_scr 
end 

def save_scr 
    @src = Scr.new(params[:scr]) 
    puts "==============================" 
    @a = params[:scr] 
    puts @a 
    puts "==============================" 
    @scr.save 
end 
end 

我满山遍野的形式，按保存按钮并出错：

You have a nil object when you didn't expect it! 
You might have expected an instance of ActiveRecord::Base. 
The error occurred while evaluating nil.save 


/home/demas/artefacts/dev/study/ruby/rails/tracker/app/controllers/inbox_controller.rb:15:in `save_scr' 
/usr/lib/ruby/gems/1.9.1/gems/actionpack-2.3.8/lib/action_controller/base.rb:1331:in `perform_action' 
/usr/lib/ruby/gems/1.9.1/gems/actionpack-2.3.8/lib/action_controller/filters.rb:617:in `call_filters' 
... 

Request 
Parameters 
{"authenticity_token"=>"m/QBN85+5Kj+Qewtl29mBl5kBtSBr1+Ixv4jxTq6Rfk=", 
"scr"=>{"id"=>"as", 
"description"=>"sa"}, 
"commit"=>"Save"} 

正如我所看到的Rails无法创建Scr类的实例。为什么？

Answer 1

def save_scr 
    @scr = Scr.new(params[:scr]) 
    puts "==============================" 
    @a = params[:scr] 
    puts @a 
    puts "==============================" 
    @scr.save 
end