Rails has_many :through nested form

Question

I have just jumped into has_many :through association. I'm trying to implement the ability to save data for all 3 tables (Physician, Patient and association table) through a single form.

My migrations:

class CreatePhysicians < ActiveRecord::Migration
  def self.up
    create_table :physicians do |t|
      t.string :name
      t.timestamps
    end
  end
end

class CreatePatients < ActiveRecord::Migration
  def self.up
    create_table :patients do |t|
      t.string :name
      t.timestamps
    end
  end
end

class CreateAppointments < ActiveRecord::Migration
  def self.up
    create_table :appointments do |t|
      t.integer :physician_id
      t.integer :patient_id
      t.date :appointment_date
      t.timestamps
    end
  end
end

My models:

class Patient < ActiveRecord::Base
  has_many :appointments
  has_many :physicians, :through => :appointments
  accepts_nested_attributes_for :appointments
  accepts_nested_attributes_for :physicians
end
class Physician < ActiveRecord::Base
  has_many :appointments
  has_many :patients, :through => :appointments
  accepts_nested_attributes_for :patients
  accepts_nested_attributes_for :appointments
end
class Appointment < ActiveRecord::Base
  belongs_to :physician
  belongs_to :patient
end

My controller:

def new
    @patient = Patient.new
    @patient.physicians.build
    @patient.appointments.build
end

My view (new.html.rb):

<% form_for(@patient) do |patient_form| %>
  <%= patient_form.error_messages %>
  <p>
    <%= patient_form.label :name, "Patient Name" %>
    <%= patient_form.text_field :name %>
  </p>
  <%  patient_form.fields_for :physicians do |physician_form| %>
    <p>
      <%= physician_form.label :name, "Physician Name" %>
      <%= physician_form.text_field :name %>
    </p>
 <% end %>

  <p>
    <%= patient_form.submit 'Create' %>
  </p>
<% end %>

<%= link_to 'Back', patients_path %>

I'm able to create a new Patient, Physician and associated record for an Appointment, but now I want to have field for appointment_date too in form. Where should I place fields for Appointments and what changes are required in my controller? I tried googling and tried this, but got stuck in some or other error implementing it.

Answer 1

Ok, this little bugger of a question stumped me for a few hours, so I'm going to post my working solution on here in hopes it shaves some time for peeps. This is for Rails 4.0 and Ruby 2.0. This also overcame a "symbol to integer conversion" issue I had.

Models:

class Patient < ActiveRecord::Base 
  has_many :appointments
  has_many :physicians, :through: :appointments
  accepts_nested_attributes_for :appointments
end 

class Appointment < ActiveRecord::Base
  belongs_to :physician 
  belongs_to :patient
  accepts_nested_attributes_for :physician
end

class Physicians < ActiveRecord::Base
  has_many :appointments
  has_many :patients, through: :appointments
end

Controller:

def new
  @patient= Patient.new 
  @appointments = @patient.appointments.build
  @physician = @appointments.build_physician 
end

def create
  Patient.new(patient_params)
end


def patient_params
   params.require(:patient).permit(:id, appointments_attributes: [:id, :appointment_time, physician_attributes: [:id ] )
end

View

<% form_for(@patient) do |patient_form| %>
  <%= patient_form.error_messages %>
  <p>
    <%= patient_form.label :name, "Patient Name" %>
    <%= patient_form.text_field :name %>
  </p>

  <% patient_form.fields_for :appointments do |appointment_form| %>
    <p>
      <%= appointment_form.label :appointment_date, "Appointment Date" %>
      <%= appointment_form.date_field :appointment_date %>
    </p>

    <% appointment_form.fields_for :physician do |physician_form| %>
      <p>
        <%= physician_form.label :name, "Physician Name" %>
        <%= physician_form.text_field :name %>
      </p>
    <% end %>
  <% end %>

  <p>
    <%= patient_form.submit 'Create' %>
  </p>
<% end %>

<%= link_to 'Back', patients_path %>

Answer 2

"i got it working. I just changed models as follows" : quoted from Shruti in the comments above

class Patient < ActiveRecord::Base 
  has_many :appointments, :dependent => :destroy 
  has_many :physicians, :through => :appointments
  accepts_nested_attributes_for :appointments
end 

class Appointment < ActiveRecord::Base
  belongs_to :physician 
  belongs_to :patient
  accepts_nested_attributes_for :physician
end

Answer 3

Your patient class accepts nested attributes for both physicians and appointments. Try adding another fields_for method for appointment.

<% form_for(@patient) do |patient_form| %>
  <%= patient_form.error_messages %>
  <p>
    <%= patient_form.label :name, "Patient Name" %>
    <%= patient_form.text_field :name %>
  </p>

  <% patient_form.fields_for :physicians do |physician_form| %>
    <p>
      <%= physician_form.label :name, "Physician Name" %>
      <%= physician_form.text_field :name %>
    </p>
  <% end %>

  <% patient_form.fields_for :appointments do |appointment_form| %>
    <p>
      <%= appointment_form.label :appointment_date, "Appointment Date" %>
      <%= appointment_form.date_field :appointment_date %>
    </p>
  <% end %>

  <p>
    <%= patient_form.submit 'Create' %>
  </p>
<% end %>

<%= link_to 'Back', patients_path %>