CODEWITHSUNDEEP
ruby-on-railsruby-on-rails-4rails-activerecord
Alexander
Alexander

Reputation: 4219

Creating and Updating with has_many: through in Rails

I'm having quite a bit of trouble with assigning has_many: through in Rails 4.

I have a functioning has_many: through with the table products and programs joined at the table program_products. My models are functioning correctly, as Product.programs = Program.all successfully assigns programs to my products. However, I cannot figure out how to gain that functionality in the view.

I've read that the most common way is with a collection_check_boxes, so I devised the following in my form view:

<%= form_for(@product) do |f| %>
    <%= f.collection_check_boxes(:programs, Program.all, :id, :name ) %>
    <%= f.submit %>
<% end %>

This gives me HTML output of 

<input type="checkbox" value="1" name="product[programs][]" id="product_programs_1">
<input type="checkbox" value="2" name="product[programs][]" id="product_programs_2">

and so on.

When I submit my form, I get this response in the params:

{"utf8"=>"✓",
 "_method"=>"patch",
 "authenticity_token"=>"xxx",
 "product"=>{"name"=>"Test",
 "description"=>"desc test",
 "price"=>"10",
 "programs"=>["1",
 "2",
 "3",
 ""]},
 "commit"=>"Update Product",
 "id"=>"18"}

With no errors. However, my database never actually updates, so I can't figure out what's going wrong. Here are the important bits of my controllers:

products_controller.rb (main CRUD controller)

def update
    @product = Product.find(params[:id])
    if @product.update_attributes(product_params)
        redirect_to(pages_dashboard_path)
    end
end

  private

  def product_params
    params.require(:product).permit(:name, :description, :price, :programs)
  end

I can't figure out what's going wrong, since I'm not getting any outright errors. The documentation for collection_check_boxes on Rails is rather confusing, so I suspect that my error may lie in that setup.

Thanks

Upvotes: 0

Views: 84

Answers (1)

Almaron
Almaron

Reputation: 4147

I think you should use program_ids instead of programs in your collection_check_boxes call. And make sure to change that in the permition method as well.

Upvotes: 1

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