1 files changed, 14 insertions, 0 deletions
diff --git a/lib/arel/engines/memory/primitives.rb b/lib/arel/engines/memory/primitives.rb
index 77d4c1a52c..f8bbcedb55 100644
--- a/lib/arel/engines/memory/primitives.rb
+++ b/lib/arel/engines/memory/primitives.rb
@@ -10,4 +10,18 @@ module Arel
       value
     end
   end
+  
+  class Ordering
+    def eval(row1, row2)
+      (attribute.eval(row1) <=> attribute.eval(row2)) * direction
+    end
+  end
+  
+  class Descending < Ordering
+    def direction; -1 end
+  end
+  
+  class Ascending < Ordering
+    def direction; 1 end
+  end
 end
 \ No newline at end of file