rails 3.2更新has_many：通过

Question

我在这一个非常接近，但抓住了一个小细节。我正在尝试更新has_many：through关系。当我提交编辑表单时，我无法提取我想更新的适当属性。更新发货数量的循环不会使用正确的值更新该字段。我怎样才能从params [：product_shipments]哈希中只提取qty_shipped属性？

This is the contents of my params[:product_shipments] hash that the update action is working with 

"product_shipments"=> {"82"=>{"qty_shipped"=>"234"}, 
         "83"=>{"qty_shipped"=>"324"}, 
         "84"=>{"qty_shipped"=>"324"}}, 
         "commit"=>"Update Shipment", "id"=>"250"} 

其中有我需要更新发货，因为@ shipment.product_shipments循环额度更新只适用于shipment_id的所有信息。我的问题是，这是通过更新动作

ProductShipment Load (0.3ms) SELECT `product_shipments`.* FROM `product_shipments` WHERE `product_shipments`.`shipment_id` = 250 
BEGIN 
UPDATE `product_shipments` SET `qty_shipped` = 1 WHERE `product_shipments`.`id` = 82 
COMMIT 
BEGIN 
UPDATE `product_shipments` SET `qty_shipped` = 1 WHERE `product_shipments`.`id` = 83 
COMMIT 
BEGIN 
UPDATE `product_shipments` SET `qty_shipped` = 1 WHERE `product_shipments`.`id` = 84 
COMMIT 

叫下面的SQL和这里是产生上面的SQL更新操作：

def update 
    @shipment = Shipment.find(params[:id]) 
    @shipment.update_attributes(params[:shipment]) 

    @shipment.product_shipments.each do |shipment| 
    shipment.update_attributes(:qty_shipped=> params[:product_shipments]) 
    end 

    respond_with @shipment, :location => shipments_url 
end 

使用rbates nested_forms宝石不可取的，因为我想为了学习轨道工作的目的，弄清楚这一点。

<%= hidden_field_tag("product_shipments[][#{product_shipment.id}]") %> 
<%= hidden_field_tag("product_shipments[][product_id]", product_shipment.id) %> 
<%= text_field_tag "product_shipments[][qty_shipped]", product_shipment.qty_shipped,:class => 'shipment_qty_field'%>&nbsp<%=[email protected]_name %> 

Answer 1

@shipment.product_shipments.each do |product_shipment| 
    product_shipment.update_attributes(:qty_shipped => params[:product_shipments][product_shipment.id][:qty_shipped]) 
end 

你不应该做这一切，只需使用嵌套表格。这是Rails！

http://railscasts.com/episodes/196-nested-model-form-part-1

您的PARAMS应该是这样的

{:product_shipments => { 79 => { :qty_shipped => 450 }, 80 => { :qty_shipped => 35 } }, :shipment_id => 1 } 

为了得到你应该命名这样

<input name="product_shipments[79][qty_shipped]" value="450" /> 
<input name="product_shipments[80][qty_shipped]" value="35" /> 

你的领域要生成，

<% @shipment.product_shipments.each do |product_shipment| %> 
    <%= text_field_tag "product_shipments[#{product_shipment.id}][qty_shipped]", product_shipment.qty_shipped || 0 %> 
<% end %>