Controllers with AR vs Perpetuity

articles_controller.rb

class ArticlesController < ApplicationController
  # with ActiveRecord
  def create
    @article = Article.new(params[:article])
    
    if @article.save
      redirect_to @article, notice: 'Article created!'
    else
      render :new
    end
  end
  
  # with Perpetuity
  def create
    @article = Article.new(params[:article])
    
    if @article.valid?
      article_mapper.insert @article
      redirect_to @article, notice: 'Article created!'
    else
      render :new
    end
  end
  
  # I memoize mappers to get the benefit of their identity map
  def article_mapper
    @article_mapper ||= Perpetuity[Article]
  end
end