$: << File.dirname(__FILE__) require "connect" require "logger" #ActiveRecord::Base.logger = Logger.new(STDERR) require "rubygems" require "active_record" ActiveRecord::Schema.define do #START:migration create_table :products, :force => true do |t| t.string :title t.text :description # ... t.integer :line_items_count, :default => 0 end #END:migration create_table :line_items, :force => true do |t| t.integer :product_id t.integer :order_id t.integer :quantity t.decimal :unit_price, :precision => 8, :scale => 2 end end class Product < ActiveRecord::Base has_many :line_items end #START:line_item class LineItem < ActiveRecord::Base belongs_to :product, :counter_cache => true end #END:line_item #START:count_issue product = Product.create(:title => "Programming Ruby", :description => " ... ") line_item = LineItem.new line_item.product = product line_item.save puts "In memory size = #{product.line_items.size}" #=> 0 puts "Refreshed size = #{product.line_items(:refresh).size}" #=> 1 #END:count_issue LineItem.delete_all Product.delete_all #START:count_fix product = Product.create(:title => "Programming Ruby", :description => " ... ") product.line_items.create puts "In memory size = #{product.line_items.size}" #=> 1 puts "Refreshed size = #{product.line_items(:refresh).size}" #=> 1 #END:count_fix