split up Session into Session/LegacySession, added some new constructor args

created AbstractEngine class which provides base for SQLEngine and will also
provide base for ConnectionProxy, so SQL binding can be to an engine or specific
connection resource
ClauseElements get using() method which can take AbstractEngines for execution
made more separation between SchemaItems and bound engine

1 files changed, 3 insertions, 2 deletions

diff --git a/lib/sqlalchemy/mapping/query.py b/lib/sqlalchemy/mapping/query.py
index 09c2b9b6e..950c2be42 100644
--- a/lib/sqlalchemy/mapping/query.py
+++ b/lib/sqlalchemy/mapping/query.py
@@ -10,6 +10,7 @@ class Query(object):
         self.mapper = mapper
         self.always_refresh = kwargs.pop('always_refresh', self.mapper.always_refresh)
         self.order_by = kwargs.pop('order_by', self.mapper.order_by)
+        self.extension = kwargs.pop('extension', self.mapper.extension)
         self._session = kwargs.pop('session', None)
         if not hasattr(mapper, '_get_clause'):
             _get_clause = sql.and_()
@@ -66,7 +67,7 @@ class Query(object):
 
         e.g.   result = usermapper.select_by(user_name = 'fred')
         """
-        ret = self.mapper.extension.select_by(self, *args, **params)
+        ret = self.extension.select_by(self, *args, **params)
         if ret is not mapper.EXT_PASS:
             return ret
         return self.select_whereclause(self._by_clause(*args, **params))
@@ -116,7 +117,7 @@ class Query(object):
         in this case, the developer must insure that an adequate set of columns exists in the 
         rowset with which to build new object instances."""
 
-        ret = self.mapper.extension.select(self, arg=arg, **kwargs)
+        ret = self.extension.select(self, arg=arg, **kwargs)
         if ret is not mapper.EXT_PASS:
             return ret
         elif arg is not None and isinstance(arg, sql.Selectable):