lib/arel/algebra/relations/operations/order.rb in arel-0.3.1 vs lib/arel/algebra/relations/operations/order.rb in arel-0.3.2

@@ -1,8 +1,9 @@
 module Arel
   class Order < Compound
     attributes :relation, :orderings
-    deriving :==
+    deriving   :==
+    requires   :ordering
 
     def initialize(relation, *orderings, &block)
       @relation = relation
       @orderings = (orderings + arguments_from_block(relation, &block)) \
         .collect { |o| o.bind(relation) }