- fixed propagation of operate() for aliased relation descriptors

- ColumnEntity gets a selectable

3 files changed, 9 insertions, 2 deletions

diff --git a/lib/sqlalchemy/orm/properties.py b/lib/sqlalchemy/orm/properties.py
index 64f2f700d..8d31963c3 100644
--- a/lib/sqlalchemy/orm/properties.py
+++ b/lib/sqlalchemy/orm/properties.py
@@ -306,6 +306,12 @@ class PropertyLoader(StrategizedProperty):
         
         def __clause_element__(self):
             return self.prop.parent._with_polymorphic_selectable
+
+        def operate(self, op, *other, **kwargs):
+            return op(self, *other, **kwargs)
+
+        def reverse_operate(self, op, other, **kwargs):
+            return op(self, *other, **kwargs)
             
         def of_type(self, cls):
             return PropertyLoader.Comparator(self.prop, cls)
diff --git a/lib/sqlalchemy/orm/query.py b/lib/sqlalchemy/orm/query.py
index 31d85b15a..ec3b6344b 100644
--- a/lib/sqlalchemy/orm/query.py
+++ b/lib/sqlalchemy/orm/query.py
@@ -1489,6 +1489,7 @@ class _ColumnEntity(_QueryEntity):
             self.entity_zero = None
         
     def setup_entity(self, entity, mapper, adapter, from_obj, is_aliased_class, with_polymorphic):
+        self.selectable = from_obj
         self.froms.add(from_obj)
 
     def __resolve_expr_against_query_aliases(self, query, expr, context):
diff --git a/lib/sqlalchemy/sql/expression.py b/lib/sqlalchemy/sql/expression.py
index 9d48b31c1..f97bd0cf3 100644
--- a/lib/sqlalchemy/sql/expression.py
+++ b/lib/sqlalchemy/sql/expression.py
@@ -1200,10 +1200,10 @@ class Operators(object):
         return op
 
     def operate(self, op, *other, **kwargs):
-        raise NotImplementedError()
+        raise NotImplementedError(str(op))
 
     def reverse_operate(self, op, other, **kwargs):
-        raise NotImplementedError()
+        raise NotImplementedError(str(op))
 
 class ColumnOperators(Operators):
     """Defines comparison and math operations."""