- [feature] The of_type() construct on attributes

now accepts aliased() class constructs as well
as with_polymorphic constructs, and works with
query.join(), any(), has(), and also
eager loaders subqueryload(), joinedload(),
contains_eager()
[ticket:2438] [ticket:1106]
- a rewrite of the query path system to use an
object based approach for more succinct usage.  the system
has been designed carefully to not add an excessive method overhead.
- [feature] select() features a correlate_except()
method, auto correlates all selectables except those
passed.   Is needed here for the updated any()/has()
functionality.
- remove some old cruft from LoaderStrategy, init(),debug_callable()
- use a namedtuple for _extended_entity_info.  This method should
become standard within the orm internals
- some tweaks to the memory profile tests, number of runs can
be customized to work around pysqlite's very annoying behavior
- try to simplify PropertyOption._get_paths(), rename to _process_paths(),
returns a single list now.  overall works more completely as was needed
for of_type() functionality

1 files changed, 12 insertions, 1 deletions

diff --git a/lib/sqlalchemy/orm/attributes.py b/lib/sqlalchemy/orm/attributes.py
index 55e0291b5..e71752ab5 100644
--- a/lib/sqlalchemy/orm/attributes.py
+++ b/lib/sqlalchemy/orm/attributes.py
@@ -103,12 +103,14 @@ class QueryableAttribute(interfaces.PropComparator):
     """Base class for class-bound attributes. """
 
     def __init__(self, class_, key, impl=None, 
-                        comparator=None, parententity=None):
+                        comparator=None, parententity=None,
+                        of_type=None):
         self.class_ = class_
         self.key = key
         self.impl = impl
         self.comparator = comparator
         self.parententity = parententity
+        self._of_type = of_type
 
         manager = manager_of_class(class_)
         # manager is None in the case of AliasedClass
@@ -137,6 +139,15 @@ class QueryableAttribute(interfaces.PropComparator):
     def __clause_element__(self):
         return self.comparator.__clause_element__()
 
+    def of_type(self, cls):
+        return QueryableAttribute(
+                    self.class_,
+                    self.key,
+                    self.impl,
+                    self.comparator.of_type(cls),
+                    self.parententity,
+                    of_type=cls)
+
     def label(self, name):
         return self.__clause_element__().label(name)