diff options
Diffstat (limited to 'lib/sqlalchemy/orm/mapper.py')
| -rw-r--r-- | lib/sqlalchemy/orm/mapper.py | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py index a59a38a5b..7e88ba161 100644 --- a/lib/sqlalchemy/orm/mapper.py +++ b/lib/sqlalchemy/orm/mapper.py @@ -426,6 +426,12 @@ class Mapper(InspectionAttr): thus persisting the value to the ``discriminator`` column in the database. + .. warning:: + + Currently, **only one discriminator column may be set**, typically + on the base-most class in the hierarchy. "Cascading" polymorphic + columns are not yet supported. + .. seealso:: :ref:`inheritance_toplevel` @@ -1080,6 +1086,9 @@ class Mapper(InspectionAttr): auto-session attachment logic. """ + + # when using declarative as of 1.0, the register_class has + # already happened from within declarative. manager = attributes.manager_of_class(self.class_) if self.non_primary: @@ -1102,18 +1111,14 @@ class Mapper(InspectionAttr): "create a non primary Mapper. clear_mappers() will " "remove *all* current mappers from all classes." % self.class_) - # else: - # a ClassManager may already exist as - # ClassManager.instrument_attribute() creates - # new managers for each subclass if they don't yet exist. + + if manager is None: + manager = instrumentation.register_class(self.class_) _mapper_registry[self] = True self.dispatch.instrument_class(self, self.class_) - if manager is None: - manager = instrumentation.register_class(self.class_) - self.class_manager = manager manager.mapper = self @@ -2649,7 +2654,7 @@ def configure_mappers(): mapper._expire_memoizations() mapper.dispatch.mapper_configured( mapper, mapper.class_) - except: + except Exception: exc = sys.exc_info()[1] if not hasattr(exc, '_configure_failed'): mapper._configure_failed = exc |