has_many :through NameError: uninitialized constant

Question

I just want to make a little join table, eventually storing extra info on that join (which is why I'm not using HABTM). From the rails documentation of associations I've created the following models:

class Physician < ActiveRecord::Base
  has_many :appointments
  has_many :patients, :through => :appointments
end

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

class Appointment < ActiveRecord::Base
  belongs_to :physicians
  belongs_to :patients
end

my schema looks like this:

ActiveRecord::Schema.define(:version => 20130115211859) do

  create_table "appointments", :force => true do |t|
    t.datetime "date"
    t.datetime "created_at",   :null => false
    t.datetime "updated_at",   :null => false
    t.integer  "patient_id"
    t.integer  "physician_id"
  end

  create_table "patients", :force => true do |t|
    t.string   "name"
    t.datetime "created_at", :null => false
    t.datetime "updated_at", :null => false
  end

  create_table "physicians", :force => true do |t|
    t.string   "name"
    t.datetime "created_at", :null => false
    t.datetime "updated_at", :null => false
  end

end

When I'm in the console and I create a physician and patient instance:

@patient = Patient.create!
@physician = Physician.create!

And try to associate one to the other

@physician.patients << @patient

I get

NameError: uninitialized constant Physician::Patients

Questions about this example have been asked before but none have address my scenario. Any ideas?

Thanks, Neil, rails newbie.

Answer 1

The belongs_to calls in your Appointment model should take a singular form, not a plural form:

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