## Model code
class Product
  define_index do
    indexes :name, :sortable => true
    indexes :description
    indexes manufacturer_name
    indexes merchant.name, :as => :merchant_name
    indexes category.name, :as => :category_name
    indexes price, :sortable => true
  end
end

## Results
> Product.search("foo", :order => :name).map(&:name)
# => ["100 Superstar Guitar Sounds On A Stompbox Budget", "21st Century Rock Buskers Book 2", "21st Century Rock Tab 2", "21st Century Rock Tab 3", "21st Century Rock: Play-Along Chord Songbook", "A Song's Best Friend: John Denver Remembered", "Akim-Foo the History of a Failure (Gold Coast 1873-74 Campaign)", "Best of Foo Fighters: Guitar Signature Licks", "Blade Dancer", "Buzz The Pop Quiz Solus", "Buzz! The Pop Quiz Bundle", "Buzz! The Pop Quiz Bundle - PlayStation 2", "Buzz! The Pop Quiz Solus - PlayStation 2", "CD - Art", "Cab Calloway - The Swing Era [Spanish Import]", "Cinema Of Vengeance", "Coheed And Cambria / No World For Tomorrow", "Coheed And Cambria / No World For Tomorrow", "Complete Music Foo Viola And Piano [Sacd/Cd Hybrid]", "Counting Crows / Saturday Nights And Sunday Mornings"]
> Product.search("foo", :order => :category_name).map(&:name)
# => []