在Rails4中使用accepts_nested_attributes_for时更新未发生

Question

我正在尝试使用Rails4更新ActiveRecord中的accepts_nested_attributes_for字段，但是没有发生。

我的活动课，

t.string :name
      t.string :slug
      t.string :description
      t.integer :total_capacity
      t.string :url
      t.integer :invite_only
      t.integer :is_public
      t.integer :event_type_id
      t.integer :event_ticketing
      t.integer :company_id
      t.integer :client_id
      t.attachment :display_photo

和EventTiming类，

t.date :date
      t.time :start_time
      t.time :end_time
      t.integer :event_id
      t.integer :user_id
      t.integer :company_id

我已经完成了，在活动课中

has_many :event_timings, :dependent => :destroy
accepts_nested_attributes_for :event_timings, allow_destroy: true

在控制器中

def event_params
  params.require(:event).permit!
end

edit.html.erb

<%= f.fields_for :event_timings do |builder| %>
   <%= render :partial => 'events/event_timing_fields', 
              :locals => { :f => builder } %>
<% end %>

更新的日志信息是，

Started PATCH "/events/test-dance" for 127.0.0.1 at 2014-06-24 16:44:46 +0530
Processing by EventsController#update as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"/O06IfwhCDecm//oGuWwGXAIRaCjwbl0s/7CZucOySU=", "event"=>{"name"=>"Test Dance", "url"=>"www.mink7.com", "event_type_id"=>"", "total_capacity"=>"100", "event_ticketing"=>"0", "event_timings_attributes"=>{"0"=>{"date(1i)"=>"2014", "date(2i)"=>"12", "date(3i)"=>"24", "start_time(1i)"=>"2000", "start_time(2i)"=>"1", "start_time(3i)"=>"1", "start_time(4i)"=>"15", "start_time(5i)"=>"29", "end_time(1i)"=>"2000", "end_time(2i)"=>"1", "end_time(3i)"=>"1", "end_time(4i)"=>"15", "end_time(5i)"=>"29", "user_id"=>"2", "id"=>"1"}}, "description"=>"Come and enjoy...!!!"}, "commit"=>"Next", "id"=>"test-dance"}
  User Load (0.4ms)  SELECT `users`.* FROM `users` WHERE `users`.`id` = 2 ORDER BY `users`.`id` ASC LIMIT 1
  Company Load (0.3ms)  SELECT `companies`.* FROM `companies` WHERE `companies`.`user_id` = 2
  Event Load (0.3ms)  SELECT `events`.* FROM `events` WHERE `events`.`slug` = 'test-dance' ORDER BY `events`.`id` ASC LIMIT 1
   (0.2ms)  BEGIN
  EventTiming Load (0.7ms)  SELECT `event_timings`.* FROM `event_timings` WHERE `event_timings`.`event_id` = 1 AND `event_timings`.`id` IN (1)
   (0.3ms)  COMMIT
Redirected to http://localhost:3000/events/test-dance
Completed 302 Found in 21ms (ActiveRecord: 2.2ms)

我的更新功能很简单

def update
    respond_to do |format|
      if @event.update(event_params)
        format.html { redirect_to @event, notice: 'Event was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: 'edit' }
        format.json { render json: @event.errors, status: :unprocessable_entity }
      end
    end
  end

请帮我！！！