Rails Rich Association - Overwriting to association model

Suppose we have three models PATIENTS, NURSES, and their association model APPOINTMENTS.

This week all patients have to meet with their nurses.

A patient has many nurses, and a nurse has many patients. Likewise, a patient has many appointments, but only one per nurse, and a nurse has many appointments, but only one per patient.

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


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


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

Obviously, the APPOINTMENT belongs to both the patient and the nurse.

However, I also want a way for the nurse to be able to tick off whether or not the patient showed up. I implemented this within the migration like such:

class CreateAppointments < ActiveRecord::Migration
  def self.up
    create_table :appointments do |t|
      t.references :patient
      t.references :nurse
      t.boolean "present", :default => false
      t.timestamps
    end
    add_index :job_enrollments, ['patient_id', 'nurse_id']
  end

  def self.down
    drop_table :appointments
  end

end

In the console, I could create an instance of everything, and could do the following:

appt = Appointment.new
patient = Patient.new
nurse = Nurse.new

patient.appointments << appt
nurse.appointments << appt

Now, here comes the question: How do I implement it so that the Nurse in that appointment is able to edit the value of the boolean to TRUE? So far, I can change the value of the instance of the appointment by typing:

appt.present = true

But this not what I want. I want the nurse to be able to modify this association, and lock out the patient from changing anything.

Should I simply not be using rich associations for this?

Solution

I'm assuming your question is about how to use these associations. You can recall and modify the appointment record after the appointment is kept, like so:

# current_nurse is the nurse using the system and reporting
appt = current_nurse.appointments.where(:patient_id => params[:patient_id]).first
appt.update_attribute :present, true

To prevent the patient from accessing and modifying the appointment, you would need an authentication mechanism, such as devise. Then only grant Nurses permission to access the system.