at the very least I'd start with writing out the query exactly using
join()/outerjoin(), then seeing if contains_eager() can do it. I'm
not sure that the current traversal of attributes within the loading
process can handle it, though.
On Aug 29, 2009, at 5:50 PM, Jae Kwon wrote:
>
> oops, it looks like the second form
> (session.query(Item).with_polymorphic([FooItem,
> BarItem]).options(eagerload(FooItem.foochild, BarItem.barchild)))
> works fine.
>
> should i go ahead and try to write test cases?
>
> - Jae
>
> On Aug 29, 2009, at 2:23 PM, Jae Kwon wrote:
>
>> I looked at this further, i think I got it working half way.
>>
>> Index: lib/sqlalchemy/orm/util.py
>> ===================================================================
>> --- lib/sqlalchemy/orm/util.py (revision 6072)
>> +++ lib/sqlalchemy/orm/util.py (working copy)
>> @@ -387,6 +387,7 @@
>> if left_mapper or right_mapper:
>> self._orm_mappers = (left_mapper, right_mapper)
>>
>> + parent_mapper =
>> onclause.parententity._AliasedClass__mapper
>> if isinstance(onclause, basestring):
>> prop = left_mapper.get_property(onclause)
>> elif isinstance(onclause, attributes.QueryableAttribute):
>> @@ -411,6 +412,9 @@
>> onclause = sj
>> else:
>> onclause = pj
>> +
>> + if parent_mapper._single_table_criterion:
>> + onclause = sql.and_(onclause,
>> parent_mapper._single_table_criterion)
>> self._target_adapter = target_adapter
>>
>> expression.Join.__init__(self, left, right, onclause, isouter)
>>
>>
>> It works for queries of the form :
>> items =
>> session
>> .query
>> (Item).with_polymorphic([FooItem]).options(eagerload(FooItem.child))
>> but not :
>> items = session.query(Item).with_polymorphic([FooItem,
>> BarItem]).options(eagerload(FooItem.foochild, BarItem.barchild))
>>
>> I'll keep trying around for a solution that solves the above, and
>> then hopefully someone more knowledgeable can pick it up or guide me.
>>
>> - Jae
>>
>>
>>
>>
>>
>>
>> On Aug 28, 2009, at 4:43 PM, Jae Kwon wrote:
>>
>>>
>>> I've seen similar discussions here, but it's been a while so perhaps
>>> things have changed.
>>>
>>> class Foo(Base):
>>> __tablename__ = 'foo'
>>> type = Column(Integer)
>>> __mapper_args__ = {'polymorphic_on': type}
>>> ...
>>>
>>> class BarFoo(Foo):
>>> __mapper_args__ = {'polymorphic_identity': 1}
>>> bar_id = Column(Integer)
>>> # relations
>>> bar = relation('Bar')
>>>
>>> class BazFoo(Foo):
>>> __mapper_args__ = {'polymorphic_identity': 2}
>>> baz_id = Column(Integer)
>>> # relations
>>> baz = relation('Baz')
>>>
>>> ## assume existence of Bar and Baz objects
>>>
>>> Is there a way to say, query all Foo objects while eager-loading the
>>> bar/baz relations?
>>>
>>> - Jae
>>>
>>>
>>>>>
>>
>
>
> >
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