thanks, this is
https://bitbucket.org/zzzeek/sqlalchemy/issues/3874/bundle-does-not-provide-entities-fails-on
and the gerrit should merge today.
On 12/19/2016 11:58 AM, Michael Williamson wrote:
Hello!
When selecting from a polymorphic table using a bundle, the query seems
to drop the condition on the discriminator. For instance, suppose we
have an Employee class that has a name column, with subclasses Manager
and Engineer. When I query for Manager.name, I get back the names of
just the managers. When I query for Manager.name as part of a bundle,
I get back the names of both managers and engineers. Looking at the SQL,
the latter query is missing the WHERE clause for the discriminator
altogether.
Full example with output below. Any pointers on whether this is a bug
or I'm doing something wrong/weird would be appreciated.
Thanks
Michael
from sqlalchemy import *
from sqlalchemy.orm import *
from sqlalchemy.ext.declarative import declarative_base
Base = declarative_base()
class Employee(Base):
__tablename__ = 'employee'
id = Column(Integer, primary_key=True)
type = Column(String(50))
name = Column(String(30))
__mapper_args__ = {
'polymorphic_identity': 'employee',
'polymorphic_on': type,
'with_polymorphic': '*'
}
class Engineer(Employee):
__mapper_args__ = {
'polymorphic_identity': 'engineer',
}
class Manager(Employee):
__mapper_args__ = {
'polymorphic_identity': 'manager',
}
e = create_engine("sqlite://", echo=True)
Base.metadata.create_all(e)
s = Session(e)
s.add_all([
Engineer(name='e1'),
Engineer(name='e2'),
Manager(name='m1'),
])
s.commit()
print(s.query(Manager.name).select_from(Manager).all())
print(s.query(Bundle("name",
Manager.name)).select_from(Manager).all())
Output:
2016-12-19 16:48:39,502 INFO sqlalchemy.engine.base.Engine SELECT
employee.name AS employee_name
FROM employee
WHERE employee.type IN (?)
2016-12-19 16:48:39,502 INFO sqlalchemy.engine.base.Engine ('manager',)
[(u'm1',)]
2016-12-19 16:48:39,503 INFO sqlalchemy.engine.base.Engine SELECT
employee.name AS employee_name
FROM employee
2016-12-19 16:48:39,503 INFO sqlalchemy.engine.base.Engine ()
[((u'e1',),), ((u'e2',),), ((u'm1',),)]
--
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The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
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