I try to delete data, but sqlalchemy tried to do it twice, and rollback
Base Postgresql
version 9.6
sqlalchemy 1.0.14
psycopg2 2.7.3.1
class IdentifiedObject(Base):
__tablename__ = 'identifiedobject'
mRID = Column(UUID,
server_default=sqlalchemy.text("uuid_generate_v4()"), primary_key=True)
name = Column(String)
polymorphic_type = Column(String, nullable=False)
__mapper_args__={'polymorphic_identity':__tablename__,'polymorphic_on':polymorphic_type}
assoc_1 = Table("assoc_1", Base.metadata,
Column("cars_mRID", None, ForeignKey("cars.mRID")),
Column("games_mRID", None, ForeignKey("games.mRID")))
class Cars(IdentifiedObject):
__tablename__='cars'
mRID = Column(None, ForeignKey('identifiedobject.mRID'),
primary_key=True)
polymorphic_type = Column(String, nullable=False)
__mapper_args__={'polymorphic_identity':__tablename__,'inherit_condition':
mRID == IdentifiedObject.mRID,'polymorphic_on':polymorphic_type}
status = Column(String)
Games = relationship("Games", secondary = "assoc_1",
back_populates="Cars", primaryjoin="(cars.c.mRID==assoc_1.c.cars_mRID)")
class Games(IdentifiedObject):
__tablename__='games'
mRID = Column(None, ForeignKey('identifiedobject.mRID'),
primary_key=True)
polymorphic_type = Column(String, nullable=False)
__mapper_args__={'polymorphic_identity':__tablename__,'inherit_condition':
mRID == IdentifiedObject.mRID,'polymorphic_on':polymorphic_type}
status = Column(String)
Cars = relationship("Cars", secondary = "assoc_1",
back_populates="Games", primaryjoin="(games.c.mRID==assoc_1.c.games_mRID)")
Base.metadata.create_all(engine)
Base.prepare(engine, reflect=True)
session = Session(bind=engine)
session.add(IdentifiedObject())
games=Games(Cars=[Cars(),Cars()])
session.add (games)
session.commit()
session.close()
session.delete(games)
session.commit()
And now we found a exception
2017-09-29 09:17:44,996 INFO sqlalchemy.engine.base.Engine SELECT
cars."mRID" AS "cars_mRID", identifiedobject."mRID" AS
"identifiedobject_mRID", identifiedobject.name AS identifiedobject_name,
cars.polymorphic_type AS cars_polymorphic_type,
identifiedobject.polymorphic_type AS identifiedobject_polymorphic_type,
cars.status AS cars_status
FROM assoc_1, identifiedobject JOIN cars ON cars."mRID" =
identifiedobject."mRID"
WHERE %(param_1)s = assoc_1."games_mRID" AND cars."mRID" =
assoc_1."cars_mRID"
2017-09-29 09:17:44,996 INFO sqlalchemy.engine.base.Engine {'param_1':
UUID('7a960989-5e3e-45dc-87c1-1b62ffa3694a')}
2017-09-29 09:17:44,997 INFO sqlalchemy.engine.base.Engine DELETE FROM
assoc_1 WHERE assoc_1."cars_mRID" = %(cars_mRID)s AND assoc_1."games_mRID"
= %(games_mRID)s
2017-09-29 09:17:44,998 INFO sqlalchemy.engine.base.Engine
({'games_mRID': UUID('7a960989-5e3e-45dc-87c1-1b62ffa3694a'), 'cars_mRID':
UUID('a3135561-e416-45c0-b9f8-aead59ef6b34')}, {'games_mRID':
UUID('7a960989-5e3e-45dc-87c1-1b62ffa3694a'), 'cars_mRID':
UUID('b77b9dc4-65da-45ea-be52-dc53e2bcd74b')})
2017-09-29 09:17:44,998 INFO sqlalchemy.engine.base.Engine DELETE FROM
assoc_1 WHERE assoc_1."cars_mRID" = %(cars_mRID)s AND assoc_1."games_mRID"
= %(games_mRID)s
2017-09-29 09:17:44,999 INFO sqlalchemy.engine.base.Engine
({'games_mRID': UUID('7a960989-5e3e-45dc-87c1-1b62ffa3694a'), 'cars_mRID':
UUID('a3135561-e416-45c0-b9f8-aead59ef6b34')}, {'games_mRID':
UUID('7a960989-5e3e-45dc-87c1-1b62ffa3694a'), 'cars_mRID':
UUID('b77b9dc4-65da-45ea-be52-dc53e2bcd74b')})
2017-09-29 09:17:44,999 INFO sqlalchemy.engine.base.Engine ROLLBACK
Traceback (most recent call last):
File "testing.py", line 98, in <module>
session.commit()
Exception data
sqlalchemy.orm.exc.StaleDataError: DELETE statement on table 'assoc_1'
expected to delete 2 row(s); Only 0 were matched.
Haven't found on other answers
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