- merged loader_strategies branch into trunk.

- this is a wide refactoring to "attribute loader" and "options" architectures.
ColumnProperty and PropertyLoader define their loading behaivor via switchable
"strategies", and MapperOptions no longer use mapper/property copying
in order to function; they are instead propigated via QueryContext
and SelectionContext objects at query/instnaces time.
All of the copying of mappers and properties that was used to handle
inheritance as well as options() has been removed and the structure
of mappers and properties is much simpler and more clearly laid out.

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/sqlalchemy/exceptions.py b/lib/sqlalchemy/exceptions.py
index 16a288503..16df317e2 100644
--- a/lib/sqlalchemy/exceptions.py
+++ b/lib/sqlalchemy/exceptions.py
@@ -50,7 +50,11 @@ class NoSuchTableError(InvalidRequestError):
 class AssertionError(SQLAlchemyError):
     """corresponds to internal state being detected in an invalid state"""
     pass
-    
+
+class NoSuchColumnError(KeyError, SQLAlchemyError):
+    """raised by RowProxy when a nonexistent column is requested from a row"""
+    pass
+        
 class DBAPIError(SQLAlchemyError):
     """something weird happened with a particular DBAPI version"""
     def __init__(self, message, orig):