--- a/server/schemaserial.py	Thu Feb 17 18:23:41 2011 +0100
+++ b/server/schemaserial.py	Thu Feb 17 18:43:45 2011 +0100
@@ -236,12 +236,12 @@
             eschema = schema.schema_by_eid(eeid)
             relations = unique_togethers.setdefault(uniquecstreid, (eschema, []))
             rel = ertidx[releid]
-            if isinstance(rel, schemamod.RelationSchema):
-                rtype = rel.type
-            else:
+            if isinstance(rel, schemamod.RelationDefinitionSchema):
                 # not yet migrated 3.9 database ('relations' target type changed
                 # to CWRType in 3.10)
                 rtype = rel.rtype.type
+            else:
+                rtype = str(rel)
             relations[1].append(rtype)
         for eschema, unique_together in unique_togethers.itervalues():
             eschema._unique_together.append(tuple(sorted(unique_together)))