I am trying to subclass a mapped class from another package for no
other reason than to add a utility method. The polymorphic_on
condition, if it were defined, would have to be 'True'. Example:
class Mapped(declarative_base()):
# columns
class Utility(Mapped):
def is_something(self):
return 'foo'
Encouraged by the fact that session.query(Utility).first() works, I
proceeded and got an exception.
The error is
FlushError: Attempting to flush an item of type <Utility> on
collection 'Something.mapped', which is not the expected type.
Configure mapper 'Mapper|User|user' to load this subtype
polymorphically, or set enable_typechecks=False to allow subtypes.
Mismatched typeloading may cause bi-directional relationships
(backrefs) to not function properly.
I'm starting to think I should just monkey patch the original class or
just pass the Mapped() into utility()... is that the best way?
Thanks!
Daniel
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