- relationships and columns with foreign keys aren't

allowed on declarative mixins, sorry.  [ticket:1751]

1 files changed, 11 insertions, 2 deletions

diff --git a/lib/sqlalchemy/ext/declarative.py b/lib/sqlalchemy/ext/declarative.py
index ef1d3e68c..1f4658b60 100644
--- a/lib/sqlalchemy/ext/declarative.py
+++ b/lib/sqlalchemy/ext/declarative.py
@@ -507,7 +507,7 @@ Mapped instances then make usage of
 from sqlalchemy.schema import Table, Column, MetaData
 from sqlalchemy.orm import synonym as _orm_synonym, mapper, comparable_property, class_mapper
 from sqlalchemy.orm.interfaces import MapperProperty
-from sqlalchemy.orm.properties import PropertyLoader, ColumnProperty
+from sqlalchemy.orm.properties import RelationshipProperty, ColumnProperty
 from sqlalchemy.orm.util import _is_mapped_class
 from sqlalchemy import util, exceptions
 from sqlalchemy.sql import util as sql_util
@@ -543,7 +543,16 @@ def _as_declarative(cls, classname, dict_):
             for name in names:
                 obj = getattr(base,name, None)
                 if isinstance(obj, Column):
+                    if obj.foreign_keys:
+                        raise exceptions.InvalidRequestError(
+                            "Columns with foreign keys to other columns "
+                            "are not allowed on declarative mixins at this time."
+                        )
                     dict_[name]=column_copies[obj]=obj.copy()
+                elif isinstance(obj, RelationshipProperty):
+                    raise exceptions.InvalidRequestError(
+                                        "relationships are not allowed on "
+                                        "declarative mixins at this time.")
 
     # doing it this way enables these attributes to be descriptors
     get_mapper_args = '__mapper_args__' in dict_
@@ -778,7 +787,7 @@ def _deferred_relationship(cls, prop):
                     prop.parent, arg, n.args[0], cls))
         return return_cls
 
-    if isinstance(prop, PropertyLoader):
+    if isinstance(prop, RelationshipProperty):
         for attr in ('argument', 'order_by', 'primaryjoin', 'secondaryjoin',
                      'secondary', '_foreign_keys', 'remote_side'):
             v = getattr(prop, attr)