Question

Suppose I have two classes in a Rails application:

class Subject < ActiveRecord::Base  
  def children?
    Subject.where(:parent_id => self.id).length > 0
  end

 def children
   Subject.where(:parent_id => self.id)
 end 
end


class Region < ActiveRecord::Base  
  def children?
    Region.where(:parent_id => self.id).length > 0
  end

 def children
   Region.where(:parent_id => self.id)
 end 
end

What would be the best way to reduce the redundant class methods? Would I extend ActiveRecord with two new methods? If so, how could I write those two new methods to be available for both classes?

Thanks,
Mike

Answer 1

Actually what are you dealing with is has_many association.

DRY principle is very good one, but not for this case. You want to extract very simple and native stuff out off model, while it will complicate main picture.

So you can just refactor a little

class Subject < ActiveRecord::Base
  has_many :children, :class_name => "Subject", :foreign_key => :parent_id

  def children?
    children.present?
  end
end