id
subject
message
valediction
sent_people_count
deliver_by
geotarget
event_id
list_id
processed_at
deleted_at
created_at
updated_at

class Notification < ActiveRecord::Base
  # common methods/validations/associations
  ...

  def self.relate_to_details
    class_eval <<-EOF
      has_one :details, :class_name => "#{self.class.name}Detail"
      accepts_nested_attributes_for :details
      default_scope :include => :details
    EOF
  end
end

class SMS < Notification
  relate_to_details

  # sms specific methods
  ...
end

class Twitter < Notification
  relate_to_details

  # twitter specific methods
  ...
end

class Email < Notification

  # email specific methods
  ...
end

class SMSDetail < ActiveRecord::Base
  belongs_to :SMS, :class_name => "SMS"

  # sms specific validations
  ...
end

class TwiterDetail < ActiveRecord::Base
  belongs_to :twitter

  # twitter specific validations
  ...
end

has_one :details, :class_name => "#{self.class.name}Detail"

has_one :details, :class_name => "#{self.name}Detail"