diff --git a/lib/puppet/rails/inventory_node.rb b/lib/puppet/rails/inventory_node.rb
index 052745a72..52d25f032 100644
--- a/lib/puppet/rails/inventory_node.rb
+++ b/lib/puppet/rails/inventory_node.rb
@@ -1,30 +1,43 @@
 require 'puppet/rails/inventory_fact'
 
 class Puppet::Rails::InventoryNode < ::ActiveRecord::Base
   has_many :facts, :class_name => "Puppet::Rails::InventoryFact", :foreign_key => :node_id, :dependent => :delete_all
 
   if Puppet::Util.activerecord_version < 3.0
-    # For backward compatibility, add the newer name to older implementations.
-    ActiveRecord::NamedScope::ClassMethods.module_eval { alias :scope :named_scope }
-  end
+    # For backward compatibility, use the old named_scope with pre 3.0 activerecord
+    named_scope :has_fact_with_value, lambda { |name,value|
+      {
+        :conditions => ["inventory_facts.name = ? AND inventory_facts.value = ?", name, value.to_s],
+        :joins => :facts
+      }
+    }
 
-  scope :has_fact_with_value, lambda { |name,value|
-    {
-      :conditions => ["inventory_facts.name = ? AND inventory_facts.value = ?", name, value.to_s],
-      :joins => :facts
+    named_scope :has_fact_without_value, lambda { |name,value|
+      {
+        :conditions => ["inventory_facts.name = ? AND inventory_facts.value != ?", name, value.to_s],
+        :joins => :facts
+      }
+    }
+  else
+    # Use scope for activerecord >= 3.0
+    scope :has_fact_with_value, lambda { |name,value|
+      {
+        :conditions => ["inventory_facts.name = ? AND inventory_facts.value = ?", name, value.to_s],
+        :joins => :facts
+      }
     }
-  }
 
-  scope :has_fact_without_value, lambda { |name,value|
-    {
-      :conditions => ["inventory_facts.name = ? AND inventory_facts.value != ?", name, value.to_s],
-      :joins => :facts
+    scope :has_fact_without_value, lambda { |name,value|
+      {
+        :conditions => ["inventory_facts.name = ? AND inventory_facts.value != ?", name, value.to_s],
+        :joins => :facts
+      }
     }
-  }
+  end
 
   def facts_to_hash
     facts.inject({}) do |fact_hash,fact|
       fact_hash.merge(fact.name => fact.value)
     end
   end
 end