Rails, accepts_nested_attributes_for has_many: through with build

[Srdjan Cengic]

I have 3 models:

class Product < ActiveRecord::Base
   has_many :product_option_types
   has_many :option_types, through: :product_option_types
end

class OptionType < ActiveRecord::Base
    has_many :product_option_types
    has_many :products, through: :product_option_types
end

class ProductOptionType < ActiveRecord::Base
    belongs_to :product
    belongs_to :option_type
end

Table OptionType is predefined with following:

Now when creating new Product i need to populate also table product_option_types with product_id and option_type id: Here is the design of product_option_types table:

Far as i know i need accepts_nested_attributes_for in Product model to refference product_option_types, so in product model i need following ?

accepts_nested_attributes_for :product_option_types, allow_destroy: true

Before rendering new.html.erb then i need to build product_option_types on the following way ?

@product = Product.new
@product.product_option_types.build(position: 1)

In the view new.html.erb i'm using collection_select to display option_types:

<%= f.fields_for :product_option_types do |builder| %>
    <%= builder.label :option_type_id, "Options" %>
    <%= builder.collection_select :option_type_id, OptionType.all(order: 'name ASC'), 
                                  :id, :name, { prompt: "Select option..."} %>
<% end %>

Finally in the crate action of product controller i must permit also association attributes like:

permited = params[:product].permit(product_option_types_attributes: [:option_type_id])

So main question is, did i set up accepts_nested_attributes_for, build, collection_select and associations correctly?

+: When im building associoation with parameters like:

@product.product_option_types.build(position: 1)

Then to pass that information(position: 1) to create action i must use hidden_field in form?