On Thu, Aug 3, 2017 at 1:37 PM, Colton Allen <cmanalle...@gmail.com> wrote:
> I've got an event that's trying to update another model with a foreign key
> but it's raising a strange error that I'm having trouble debugging.
> "AttributeError: 'Join' object has no attribute 'implicit_returning'".
>
> The query worked in the past (before the OutboundModel became polymorphic).
> I'm certain the query in the update event is incorrect but I'm unsure of how
> to fix it.
>
> # Parent polymorphic models
> class OutboundModel(Model):
> __tablename__ = 'outbound'
>
> id = Column(Integer, primary_key=True)
> driver = Column(
> Enum('default', 'ses', name='outbound_driver'), default='default',
> nullable=False)
> latest_result_id = Column(Integer, ForeignKey('outbound_result.id'))
> latest_result = orm.relationship(
> 'OutboundResultModel', backref='outbound',
> foreign_keys=[latest_result_id])
>
> __mapper_args__ = {
> 'polymorphic_identity': 'default',
> 'polymorphic_on': driver,
> 'with_polymorphic': '*'
> }
>
>
> class OutboundSESModel(OutboundModel):
> __tablename__ = 'service_outbound_ses'
> __mapper_args__ = {'polymorphic_identity': 'ses'}
>
> id = Column(Integer, ForeignKey('outbound.id'), primary_key=True)
>
>
> # Child polymorphic models
> class OutboundResultModel(Model):
> __tablename__ = 'outbound_result'
>
> id = Column(Integer, primary_key=True)
> driver = Column(
> Enum('a', 'b', name='outbound_result_driver'), default='a',
> nullable=False)
> outbound_id = Column(
> Integer, ForeignKey('outbound.id'), nullable=False)
> outbound = orm.relationship(
> 'OutboundModel', backref='results', foreign_keys=[outbound_id])
> __mapper_args__ = {
> 'polymorphic_identity': 'result',
> 'polymorphic_on': kind,
> 'with_polymorphic': '*'
> }
>
>
> # The event causing the error.
> # AttributeError: 'Join' object has no attribute 'implicit_returning'
> @event.listens_for(OutboundResultModel, 'after_insert', propagate=True)
> def set_latest_outbound_result(mapper, connection, target):
> """Set the latest_outbound relationship on the Outbound parent."""
> statement = update(OutboundModel).where(
> OutboundModel.id == target.outbound_id).values(
> latest_result_id=target.id)
> connection.execute(statement)
That's Core update(), which is probably not appreciating that
OutboundModel now maps to a join() because of the with_polymorphic in
the mapper config. If you're doing Core you should call upon
OutboundModel.__table__ to eliminate any interference from the mapping
(or if that doesn't work, because i can't remember if __table__ is
going to pull in the polymorphic selectable as well, do
inspect(OutboundModel).local_table).
>
>
> --
> 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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