Question

I’m not very good with ruby so I’m very thankful for all the help offered 🙂

I have 2 models Clinic and Patient

clinics has three fields which I cache aggregates when a Patient is created

max_patients,
max_female_patients,
max_male_patients

I’m trying to wrap my brain around how to write a validation to check the following rules when adding a new Patient:

cannot have more than 37 total patients for 1 clinic,
15 female patients and 22 male patients is the standard,
however if a substitution needs to be made I can
swap out 3 male patients for 1 female,
or swap out 1 female patient for 1 male

The other nuisance is that patients are added 3 at time (on one form) and each patient can select a different clinic day.

I hope that makes sense.. I’ve been thinking about this for hours and I have a bad feeling I’m approaching this the wrong way.

Thanks for any help in advance

Answer 1

I wouldn’t create database columns for these attributes, I would
use a child-inheritable class variable through cattr_accessor
(class extension defined in ActiveSupport).

I’m not sure what you mean by:

if a substitution needs to be made I can swap out 3 male patients for
1 female, or swap out 1 female patient for 1 male

I don’t think you’ve given enough info, or it’s not clear in my mind anyway.
For example, when does a substitution need to be made? Are the appointments recurrent, or a one-off (since it’s a clinic… I assumed one-off). Anyway, hope this helps.

class Clinic
  has_many  :patients
  cattr_accessor :max_patients, :max_male_patients, :max_female_patients
  self.max_patients = 37
  self.max_male_patients = 22
  self.max_female_patients = 15
end

class Patient
  belongs_to :clinic
  has_many   :appointments
  ...
end

class Appointment
  belongs_to :patient
  before_save :switch_appt_date_if_full

  private
  def switch_appt_date_if_full
    # implementation goes here
    # note: the instances of Appointment can access the clinic's capacities through
    # self.patient.clinic.max_patients, etc...
  end
end

-Luke