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POBest approach to deal with complex nested form
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  1. POBest approach to deal with complex nested form
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    copied!<p>I have a form with products in rows and suppliers in columns. Users can enter an order quantity for each product / supplier combination.</p> <p><img src="https://i.stack.imgur.com/iCyvo.png" alt="enter image description here"></p> <p>For each Supplier, 1 Order is created. Each Order contains OrderItems. OrderItems are created for each field (Product / Supplier combination) where the user enters a quantity.</p> <p>There's a lot of handwritten code to process the submitted form.</p> <p>Is there any way to DRY up any of the code below? Or is there a better approach altogether?</p> <p>I checked out the Nested Forms Railscast but I don't see any way how I could use accepts_nested_attributes_for here because the input is two dimensional (combination of supplier and product).</p> <pre><code>class Product &lt; ActiveRecord::Base has_many :order_items end class Supplier &lt; ActiveRecord::Base has_many :orders end # groups all OrderItems for 1 Supplier class Order &lt; ActiveRecord::Base has_many :order_items belongs_to :supplier def self.create_orders_and_order_items(orders) orders.each do |supplier_id, order_items| if order_has_order_item?(order_items) order = create!( :total =&gt; 0, :supplier_id =&gt; supplier_id, :order_group_id =&gt; order_group.id ) OrderItem.create_order_items(order, order_items) # update attributes order.update(:total =&gt; order.order_items.sum(:total)) end end end def self.order_has_order_item?(order_items) sum = 0 order_items.each do |product_id, quantity| sum += quantity.to_i end sum &gt; 0 ? true : false end end # 1 OrderItem per product / supplier combination class OrderItem &lt; ActiveRecord::Base belongs_to :order belongs_to :supplier belongs_to :product def self.create_order_items(order, order_items) order_items.each do |product_id, quantity| if quantity.to_i &gt; 0 order_item = create!( :quantity =&gt; quantity, :product_id =&gt; product_id, :order_id =&gt; order.id, ) # update after creating, because methods called below are only available once object has been instantiated order_item.udpate(:total =&gt; order_item.calculate_total) end end end end class OrdersController &lt; ApplicationController def create Order.create_orders_and_order_items(params[:orders]) respond_to do |format| format.html { redirect_to :action =&gt; "index" } end end end # view: _form.html.erb &lt;table&gt; &lt;tr&gt; &lt;td&gt;Name&lt;/td&gt; &lt;% @suppliers.each do |supplier| %&gt; &lt;td COLSPAN=2&gt;&lt;%= supplier.name %&gt;&lt;/td&gt; &lt;% end %&gt; &lt;/tr&gt; &lt;% @products.each do |product| %&gt; &lt;tr&gt; &lt;td&gt;&lt;%= product.name %&gt;&lt;/td&gt; &lt;td&gt;&lt;%#= some price %&gt;&lt;/td&gt; &lt;td&gt;&lt;%= f.text_field "#{supplier.id}[#{product.id}]", :value =&gt; "" %&gt;&lt;/td&gt; &lt;/tr&gt; &lt;/table&gt; &lt;%= f.submit %&gt; # params (from memory) {"orders" =&gt; { "4" =&gt; # supplier_id, 1 Order for each Supplier { "13" =&gt; "2" } # product_id =&gt; quantity, = 1 OrderItem } } </code></pre>
 

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