Hello,
I'm working with a class inheritance structure which can be illustrated by
this example:
class Entity(object):
def __init__(self,
entity_type=EntityTypeEntity,
id=None):
self.entity_type = entity_type
self.id = id
class Person(Entity):
def __init__(self,
entity_class=None,
entity_type=EntityTypePerson,
id=None,
name_first=None,
name_last=None,
name_middle=None,
name_prefix=None,
name_suffix=None):
super(Person, self).__init__(entity_type,
id)
self.entity_class = entity_class
self.name_first = name_first
self.name_last = name_last
self.name_middle = name_middle
self.name_prefix = name_prefix
self.name_suffix = name_suffix
class SupporterPerson(Person):
def __init__(self,
entity_class=EntityClassSupporterPerson,
entity_type=EntityTypePerson,
id=None,
name_first=None,
name_last=None,
name_middle=None,
name_prefix=None,
name_suffix=None,
relationship=None):
super(SupporterPerson, self).__init__(entity_class,
entity_type,
id,
name_first,
name_last,
name_middle,
name_prefix,
name_suffix)
self.relationship = relationship
My current mappings look like this:
# Mappers
self.entity_table_mapper = mapper(
Entity,
self.entities_table,
polymorphic_on=self.entities_table.c.entity_type,
polymorphic_identity=EntityTypeEntity,
with_polymorphic='*',
properties={
'entity_type': self.entities_table.c.entity_type,
'id': self.entities_table.c.id,
}
)
self.persons_table_mapper = mapper(
Person,
self.persons_table,
polymorphic_on=self.persons_table.c.entity_class,
polymorphic_identity=EntityTypePerson,
with_polymorphic='*',
inherits=Entity,
)
self.supporter_persons_table_mapper = mapper(
SupporterPerson,
self.supporter_persons_table,
polymorphic_identity=EntityClassSupporterPerson,
with_polymorphic='*',
inherits=Person,
)
I am able to instantiate a SupporterPerson() and successfully store all
attributes correctly in their respective tables. So the mapping seems to
work well. However...
In the broader context of my application, a query to load Causes() (
sketched out below ) will eagerload a list of that causes supporters. When
supporters are eagerloaded, the supporter is reliably loaded to the level
of Person() however the attributes specific to SupporterPerson() are not
loaded. In other words, the attributes specific to the youngest child in
my class inheritance, structure are NOT loaded by the eagerload.
class Cause(object):
def __init__(self,
id=None
supporters=None):
self.id = id
self.supporters = [] if supporters is None else None
So my question is, Is there a problem with my mapping? Or is this depth of
inheritance not supported by the eagerload? Or perhaps there is something
else I'm missing altogether ( unrelated to the eagerload ) ? Any advice or
assistance would be greatly appreciated. Sorry if I'm missing something
that is already clearly stated in the documentation.
Best,
Ken
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