found a few mentions of "flat=True" that fail to specify that this
flag should **not** be used when selectable= is set, pushing extra
verbiage to that effect now. most likely with_polymorphic() should
raise an error if both flags are set.
On Wed, Mar 7, 2018 at 3:48 PM, Mike Bayer <mike...@zzzcomputing.com> wrote:
> here's a full MCVE, which with "flat=True" reproduces your issue
> exactly (send me this next time). The issue is the "flat=True", take
> that out because it isn't compatible with a concrete union - it
> implies the "aliased" flag and that gets in the way of what the
> polymorphic_union() function is doing already.
>
>
> from sqlalchemy import *
> from sqlalchemy.orm import *
> from sqlalchemy.ext.declarative import declarative_base
> from sqlalchemy.ext.declarative import declared_attr
> from sqlalchemy.ext.declarative import AbstractConcreteBase
>
> Base = declarative_base()
>
>
> class OrderItem(AbstractConcreteBase, Base):
> pass
>
>
> class OrderTestItem(OrderItem):
> __tablename__ = 'order_test_item'
>
> order_id = Column(Integer, ForeignKey("order.id"), primary_key=True)
> test_id = Column(Integer, ForeignKey("test.id"), primary_key=True)
>
> test = relationship('Test')
> order = relationship('Order')
>
> __mapper_args__ = {
> 'polymorphic_identity': 'order_test_item',
> 'concrete': True
> }
>
>
> class User(Base):
> __tablename__ = 'user'
> id = Column(Integer, primary_key=True)
>
>
> class Test(Base):
> __tablename__ = 'test'
> id = Column(Integer, primary_key=True)
>
>
> class Order(Base):
> __tablename__ = 'order'
>
> id = Column(Integer, primary_key=True)
>
> user_id = Column(Integer, ForeignKey('user.id'))
>
> user = relationship('User')
> items = relationship('OrderItem')
>
> e = create_engine("sqlite://", echo=True)
> Base.metadata.create_all(e)
>
> s = Session(e)
>
> t1, t2 = Test(), Test()
> s.add(Order(items=[OrderTestItem(test=t1), OrderTestItem(test=t2)]))
> s.commit()
>
>
> pjoin = polymorphic_union({
> 'order_test_item': OrderTestItem.__table__,
> }, 'type', 'pjoin')
>
> order_items = with_polymorphic(
> OrderItem, [OrderTestItem], selectable=pjoin)
>
>
> s = Session(e)
> order = s.query(Order).join(Order.items.of_type(order_items)).all()
>
>
>
>
> On Wed, Mar 7, 2018 at 3:36 PM, Harshvardhan Gupta
> <harshsay...@gmail.com> wrote:
>> Thanks for replying.
>> I forgot to show the error.
>> It is this:
>>
>> 1054, "Unknown column 'pjoin.order_id' in 'on clause'") [SQL: "SELECT
>> `order`.id AS order_id, `order`.rp_id AS order_rp_id, `order`.user_id AS
>> order_user_id \nFROM `order` INNER JOIN (SELECT order_test_item.order_id AS
>> order_id, order_test_item.test_id AS test_id, 'order_test_item' AS type
>> \nFROM order_test_item) AS anon_1 ON `order`.id = pjoin.order_id"
>>
>>
>>
>>
>> On Wednesday, 7 March 2018 15:28:54 UTC-5, Mike Bayer wrote:
>>>
>>> On Tue, Mar 6, 2018 at 8:36 PM, Harshvardhan Gupta
>>> <harsh...@gmail.com> wrote:
>>> > I tried to use AbstractConcreteBase for polymorphic relationships , but
>>> > I am
>>> > getting errors. The examples in sqlalchemy cover normal polymorphism
>>> > well,
>>> > but not those with Abstract Base classes.
>>> >
>>> >
>>> > I have already asked a question on stack overflow .
>>> >
>>> > The gist of the question is:
>>> >
>>> > class OrderItem(Dictifiable, AbstractConcreteBase, db.Model):
>>> > pass
>>> >
>>> >
>>> > class OrderTestItem(OrderItem):
>>> > order_id = Column(Integer, ForeignKey("order.id"), primary_key=True)
>>> > test_id = Column(Integer, ForeignKey("test.id"), primary_key=True)
>>> >
>>> > test = relationship('Test')
>>> > order = relationship('Order')
>>> >
>>> > __mapper_args__ = {
>>> > 'polymorphic_identity': 'order_test_item',
>>> > 'concrete': True
>>> > }
>>> >
>>> >
>>> >
>>> > class Order(Dictifiable, db.Model): # This class has a relation to the
>>> > polymorphic class
>>> >
>>> > id = Column(Integer, Sequence('user_id_seq'), primary_key=True)
>>> >
>>> > user_id = Column(Integer, ForeignKey('user.id'))
>>> >
>>> > user = relationship('User')
>>> > items = relationship('OrderItem')
>>> >
>>> >
>>> > I query like :
>>> >
>>> > pjoin = polymorphic_union({
>>> > 'order_test_item': OrderTestItem.__table__,
>>> > }, 'type', 'pjoin')
>>> >
>>> > order_items =
>>> > with_polymorphic(OrderItem,[OrderTestItem],selectable=pjoin,flat=True)
>>> >
>>> > And my actual query :
>>> >
>>> > order = Order.query.join(Order.items.of_type(order_items)).all()
>>> >
>>> >
>>> > I would like to know what the correct way to query these tables is, how
>>> > to
>>> > eager load polymorphic tables, and how to filter on the relationships.
>>>
>>> looks correct to me. what is "the error" ? can you provide full
>>> MCVE + complete stack trace?
>>>
>>>
>>>
>>> >
>>> > I plan to send a pull request with an example of these test cases after
>>> > I
>>> > know the answers myself.
>>> >
>>> >
>>> > --
>>> > SQLAlchemy -
>>> > The Python SQL Toolkit and Object Relational Mapper
>>> >
>>> > http://www.sqlalchemy.org/
>>> >
>>> > To post example code, please provide an MCVE: Minimal, Complete, and
>>> > Verifiable Example. See http://stackoverflow.com/help/mcve for a full
>>> > description.
>>> > ---
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>>
>> --
>> SQLAlchemy -
>> The Python SQL Toolkit and Object Relational Mapper
>>
>> http://www.sqlalchemy.org/
>>
>> To post example code, please provide an MCVE: Minimal, Complete, and
>> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
>> description.
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--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
To post example code, please provide an MCVE: Minimal, Complete, and Verifiable
Example. See http://stackoverflow.com/help/mcve for a full description.
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