How to use an hstore data type field in a form and store in database in Rails 4?

Question

I have the following requirement: model is called Medical; it has a Doctor Type and a Treatment Type; there can be multiple Doctor Types and Treatment Types chosen for a Medical model.

I am trying to avoid creating models for Doctor Type and Treatment Type. They are basically a collection that the application provides its users. I am trying to store them on the Medical model as hstore fields.

I did the following...

Added a migration for hstore:

   class AddHstore < ActiveRecord::Migration 
    def up
     enable_extension :hstore
    end

    def down
     disable_extension :hstore
    end
  end

Added migration to add hstore field:

class AddDataToMedical < ActiveRecord::Migration
  def change
    add_column :medical, :data, :hstore
  end
end

Added the following to the model:

class Medical < ActiveRecord::Base

    DOCTOR_TYPE = ['MD', 'Specialist', 'DO', 'Other']
    TREATMENT_TYPE = ['PT', 'Chiro', 'Meds', 'Other']

    store_accessor :data, :doctor_type, :treatment_type
...

Added the following into strong_params:

 # Never trust parameters from the scary internet, only allow the white list through.
def medical_params
  params.require(:medical).permit(:total_med_bills, :subrogated_amount, :injuries_within_three_days, :length_of_treatment, 
                              :length_of_treatment_unit, :injury_summary, :medical_summary, 
                              :earnings_lost, :treatment_gap, :injections, :hospitalization, :hospital_stay_length, 
                              :hospital_stay_length_unit, :data => [:doctor_type, :treatment_type], :injuries_attributes => [:injury_type, :region, :code, :dominant_side, :joint_fracture,
                              :displaced_fracture, :disfigurement, :impairment, :permanence, :disabled,
                              :disabled_percent, :surgery, :surgery_count, :surgery_type, :casted_fracture,
                              :stitches, :future_surgery, :future_medicals, :id])

end

then added the new fields to the form:

<%= simple_form_for([@case, @medical]) do |f| %>
    <%= f.input :total_med_bills %>
    <%= f.input :length_of_treatment %>
    <%= f.simple_fields_for :data do |d| %>
      <%= d.input :doctor_type, as: :check_boxes, collection: Medical::DOCTOR_TYPE %>
      <%= d.input :treatment_type, as: :check_boxes, collection: Medical::TREATMENT_TYPE %> 
    <% end %>
    <%= f.input :injury_summary %>
...

Question is why is the data parameter empty when I do a puts params[:data] in my Update method of medicals_controller (i am only using this field in the edit)? Also why am I getting the following in my console:

Unpermitted parameters: doctor_type, treatment_type

I see that the data hash is NOT empty when I look at my console:

..."length_of_treatment"=>"", "data"=>{"doctor_type"=>["MD", "Specialist", ""], "treatment_type"=>["Meds", "Other", ""]}, "injury_summary"=>"",...

Answer 1

Since strong parameters doesn't allow scalar values in the strong parameters...I ended up doing the following...

Strong parameters:

... :data => [:doctor_type => [], :treatment_type => []] ...

doctor_type and treatment_type keys can have multiple values.