models.rb

# Model Record (Protuário)

class Record < ActiveRecord::Base
  belongs_to    :patient
  has_many        :appointments

  attr_accessible :data, :patient_id
end


# Model Appointment (Cosulta)

class Appointment < ActiveRecord::Base
  belongs_to    :record
  has_many        :asos,                                    :dependent => :destroy #Atestado de Saúde Ocupacional
  has_many        :complementary_exams,        :dependent => :destroy  #Exames Complementares, pode existir ou não em uma Consulta
  has_many        :declarations,                     :dependent => :destroy     #Declaração de comparecimento/permanência no consultório médico
  has_many        :attests, :dependent    =>    :destroy                          #Atestado             
  has_many        :requisicao_exames,            :dependent => :destroy   #Requisição para exames laboratoriais e de imagem

  accepts_nested_attributes_for :complementary_exams, reject_if: :all_blank, :allow_destroy => true

  attr_accessible :record_id, :altura, :anamnese, :categoria_exame,
                                  :conclusao, :data, :imc, :ordem_exame, :pa, :peso,
                                  :pulso, :status, :complementary_exams_attributes

  validates_numericality_of :peso, :altura

     before_create :increment_ordem_exame

    def increment_ordem_exame
      self.ordem_exame = (self.class.last.nil?) ? "1" : ((self.class.last.ordem_exame.to_i) + 1).to_s
    end

  before_create :imc

  def imc
   self.imc = (self.class.nil?) ? 1 : ((peso.to_f) / ((altura.to_f) **2))
  end
end