diff -r 4450ba4a0937 -r f0ef12e25a2f lib/thingfish/metastore/pggraph/node.rb
--- a/lib/thingfish/metastore/pggraph/node.rb	Mon Dec 14 15:43:08 2015 -0800
+++ b/lib/thingfish/metastore/pggraph/node.rb	Tue Nov 01 17:12:49 2016 -0700
@@ -75,7 +75,7 @@
 			columns.flatten!
 			ds = self
 			columns.each do |column|
-				if Thingfish::Metastore::PG::Metadata.metadata_columns.include?( column.to_sym )
+				if Thingfish::Metastore::PgGraph::Node.metadata_columns.include?( column.to_sym )
 					ds = ds.order_append( column.to_sym )
 				else
 					ds = ds.order_append( self.user_metadata_expr(column) )