Rails 3

gistfile1.rb

products = Product.where("price = 100").limit(5) # No query executed yet
products = products.order("created_at DESC")     # Adding to the query, still no execution
products.each { |product| puts product.price }   # That's when the SQL query is actually fired

class Product < ActiveRecord::Base
  named_scope :pricey, where("price > 100")
  named_scope :latest, order("created_at DESC").limit(10)
end