Suppose I am using single table polymorphic inheritance like the docs
Employee/Manager/Engineer example. I have a relationship that I want to
have a different cascade or loading strategy for, depending on the mapper.
Can I inherit from the base mapper and override the property, like this:
employee_mapper = mapper(Employee, employees_table, \
polymorphic_on=employees_table.c.type, polymorphic_identity='employee',
properties={'customer':relationship(Customer, lazy=False,
cascade='save-update,refresh-expire,merge')})
manager_mapper = mapper(Manager, inherits=employee_mapper,
polymorphic_identity='manager',
properties={'customer':relationship(Customer, lazy=True,
cascade='save-update,refresh-expire')})
engineer_mapper = mapper(Engineer, inherits=employee_mapper,
polymorphic_identity='engineer',
properties={'customer':relationship(Customer, lazy=True,
cascade='save-update,refresh-expire')})
Here, the 'customer' relationship only joined loads and merges for
Employee, not Engineer nor Manager. Is this supported?
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