I have a column_property on a polymorphic base class. When I
joinedload/subqueryload a derived class the colum_property makes the query
fail.
class A(Base):
__tablename__ = a
id = Column(Integer, primary_key=True)
type= Column(String(40), nullable=False)
__mapper_args__ = {'polymorphic_on': type}
A.anything = orm.column_property(A.id + 1000)
class B(A):
__tablename__ = b
account_id = Column(Integer, ForeignKey('a.id'), primary_key=True)
x_id= Column(Integer, ForeignKey('x.id'), nullable=False)
__mapper_args__ = {'polymorphic_identity': 'named'}
class X(Base):
__tablename__ = x
id = Column(Integer, primary_key=True)
b = orm.relationship(B
Calling:
print Session.query(X).options(joinedload(b))
produces:
SELECT x.id AS x_id,
anon_1.a_id AS anon_1_a_id,
anon_1.a_type AS anon_1_a_type,
a.id + %(id_1)s AS anon_2,
anon_1.b_account_id AS anon_1_b_account_id,
anon_1.b_x_id AS anon_1_b_x_idFROM a,
xLEFT OUTER JOIN
(SELECT a.id AS a_id,
a.TYPE AS a_type,
b.account_id AS b_account_id,
b.x_id AS b_x_id
FROM a
JOIN b ON a.id = b.account_id) AS anon_1 ON x.id = anon_1.b_x_id
It seems that the a.id + %(id_1) should changed to anon_1.a_id and a
removed from FROM or better a.id + %(id_1)s should be moved into the
sub select named anon_1. This is probably what you want if the
column_property was actually a subselect itself (which is want I'm actually
trying to do).
Am I correct in thinking that this corner case simply isn't supported yet?
Or is it a bug? Or am I doing something wrong?
Actually the above query doesn't fail outright. Although it does create a
unsuspecting join. But if the column_property instead was something like
class subA(Base):
__tablename__ = subA
id = Column(Integer, primary_key=True)
a_id = Column(Integer, ForeignKey('a.id'), nullable=False)
value = Column(Integer, nullable=False)
A.anything = orm.column_property(
select([func.sum(subA.value)], subA.a_id==A.id))
Then the sql would be:
SELECT x.id AS x_id,
anon_1.a_id AS anon_1_a_id,
anon_1.a_type AS anon_1_a_type,
(SELECT sum(subA.value) AS sum_1
FROM subA
WHERE subA.a_id = a.id) AS anon_2,
anon_1.b_account_id AS anon_1_b_account_id,
anon_1.b_x_id AS anon_1_b_x_idFROM xLEFT OUTER JOIN
(SELECT a.id AS a_id,
a.TYPE AS a_type,
b.account_id AS b_account_id,
b.x_id AS b_x_id
FROM a
JOIN b ON a.id = b.account_id) AS anon_1 ON x.id = anon_1.b_x_id
Which naturally doesn't work at all, since a.id inside the first
subselect doesn't refer to anything.
PS: I have no idea how this email is going to get formatted, please let me
know if it is impossible to read.
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