改了论坛回复不会触发修改update字段的问题

app/controllers/memos_controller.rb

@@ -57,7 +57,7 @@ class MemosController < ApplicationController
     pre_count = REPLIES_PER_PAGE
 
     @memo = @memo.root # 取出楼主，防止输入帖子id让回复作为主贴显示
-    @memo.update_attribute(:viewed_count, @memo.viewed_count.to_i + 1)
+    @memo.update_column(:viewed_count, (@memo.viewed_count.to_i + 1))
 
     page = params[:page]
     if params[:r] && page.nil?
@@ -95,11 +95,12 @@ class MemosController < ApplicationController
 
   def update
     respond_to do |format|
-      if( @memo.update_attribute(:subject, params[:memo][:subject]) && 
-           @memo.update_attribute(:content, params[:memo][:content]) &&
-           @memo.update_attribute(:sticky, params[:memo][:sticky]) &&
-           @memo.update_attribute(:lock, params[:memo][:lock])) 
+      if( @memo.update_column(:subject, params[:memo][:subject]) && 
+           @memo.update_column(:content, params[:memo][:content]) &&
+           @memo.update_column(:sticky, params[:memo][:sticky]) &&
+           @memo.update_column(:lock, params[:memo][:lock])) 
         @memo.save_attachments(params[:attachments] || (params[:memo] && params[:memo][:uploads]))
+        # @memo.root.update_attribute(:updated_at, @memo.updated_at)
         format.html {redirect_to back_memo_url, notice: "#{l :label_memo_create_succ}"}
       else
         format.html { render action: "edit" }

app/models/memo.rb

@@ -65,6 +65,7 @@ class Memo < ActiveRecord::Base
 	def reset_counters!
 		if parent && parent.id
 			Memo.update_all({:last_reply_id => parent.children.maximum(:id)}, {:id => parent.id})
+			parent.update_attribute(:updated_at, Time.now)
 		end
 		forum.reset_counters!
 	end