I am trying to order the nested form values by created_at . Here is the code which I am using :-
<%= f.fields_for :raw_materials, f.object.raw_materials.order(:created_at => 'asc'), :validate => true do |raw_material| %>
<%= render :partial => "raw_materials_details", :locals => {:raw_material => raw_material} %>
<% end %>
The form does not shows blank . When I try to <% raise f.object.raw_materials.inspect %>
I get the below mentioned data :-
#<ActiveRecord::Associations::CollectionProxy [#<RawMaterial id: nil, name: "Jam Button 9 mm Antique Silver", rate: 1.0, raw_material_wastage: 0.0, total_raw_material: 8.0, slug: nil, costing_id: nil, created_at: "2015-06-10 09:12:13", updated_at: nil, inventory_item_id: 758, costing_wastage: 0.0, pick_from_order_sheet: false>, #<RawMaterial id: nil, name: "Leather Board 1.5 MM", rate: 6.0, raw_material_wastage: 10.0, total_raw_material: 0.416666666666667, slug: nil, costing_id: nil, created_at: "2015-06-10 09:12:13", updated_at: nil, inventory_item_id: 834, costing_wastage: 12.0, pick_from_order_sheet: false>, #<RawMaterial id: nil, name: "Suede", rate: 35.0, raw_material_wastage: 40.0, total_raw_material: 2.1875, slug: nil, costing_id: nil, created_at: "2015-06-10 09:12:13", updated_at: nil, inventory_item_id: 1547, costing_wastage: 42.0, pick_from_order_sheet: false>, #<RawMaterial id: nil, name: "COW TUMBLE MARBLE BROWN", rate: 115.0, raw_material_wastage: 30.0, total_raw_material: 13.2052951388889, slug: nil, costing_id: nil, created_at: "2015-06-10 09:12:13", updated_at: nil, inventory_item_id: 139, costing_wastage: 32.0, pick_from_order_sheet: true>, #<RawMaterial id: nil, name: "Lining Allen Cooper Black Silver N (Jaq )", rate: 4.35, raw_material_wastage: 12.0, total_raw_material: 13.1076388888889, slug: nil, costing_id: nil, created_at: "2015-06-10 09:12:13", updated_at: nil, inventory_item_id: 837, costing_wastage: 14.0, pick_from_order_sheet: true>, #<RawMaterial id: nil, name: "Rubberised", rate: 30.0, raw_material_wastage: 10.0, total_raw_material: 0.583333333333333, slug: nil, costing_id: nil, created_at: "2015-06-10 09:12:13", updated_at: nil, inventory_item_id: 1294, costing_wastage: 12.0, pick_from_order_sheet: false>, #<RawMaterial id: nil, name: "Foam Sheet 4mm", rate: 2.0, raw_material_wastage: 10.0, total_raw_material: 2.39583333333333, slug: nil, costing_id: nil, created_at: "2015-06-10 09:12:13", updated_at: nil, inventory_item_id: 621, costing_wastage: 12.0, pick_from_order_sheet: false>, #<RawMaterial id: nil, name: "Runner No. 5 D-Ring Antique", rate: 2.5, raw_material_wastage: 0.0, total_raw_material: 5.0, slug: nil, costing_id: nil, created_at: "2015-06-10 09:12:13", updated_at: nil, inventory_item_id: 1303, costing_wastage: 0.0, pick_from_order_sheet: false>, #<RawMaterial id: nil, name: "Magnet Button Big Antique", rate: 10.0, raw_material_wastage: 0.0, total_raw_material: 1.0, slug: nil, costing_id: nil, created_at: "2015-06-10 09:12:13", updated_at: nil, inventory_item_id: 927, costing_wastage: 0.0, pick_from_order_sheet: false>, #<RawMaterial id: nil, name: "Kari Square 1.5\" Antique Silver ( Pedano )", rate: 15.0, raw_material_wastage: 0.0, total_raw_material: 1.0, slug: nil, costing_id: nil, created_at: "2015-06-10 09:12:13", updated_at: nil, inventory_item_id: 778, costing_wastage: 0.0, pick_from_order_sheet: false>, ...]>
What I could gather is the I might be trying to order nested_objects which has not been built yet . But I need to do it in my use case as the order of the object in which they are displayed and stored is important.
According to this answer's comment, you can use sort_by on the collection (order is ActiveRecord and will expect to ping the database):
<%= f.fields_for :raw_materials, f.object.raw_materials.sort_by(&:created_at), validate: true do |raw_material| %>