2
私はSQLALCHEMYを学習する上でいくつかの問題を抱えています。問題は私のback_populatesとの関係であると思っていますが、私はそれを忘れてしまいました。正しい方向に私を向けることができますか？SQLAlchemy - AttributeError：_reverse_property
テーブルが正常に作成され、すべては私がしようとすると、このエラーが発生し、新たなMailProviderを作成するまでの順序であるように思われます。
Traceback (most recent call last):
File "C:/Users/Music/.PyCharm2016.2/config/scratches/scratch_7.py", line 71, in <module>
gmail = MailProvider(service_provider="gmail.com")
File "<string>", line 2, in __init__
File "C:\Users\Music\mailtesterV2\lib\site-packages\sqlalchemy\orm\instrumentation.py", line 347, in _new_state_if_none
state = self._state_constructor(instance, self)
File "C:\Users\Music\mailtesterV2\lib\site-packages\sqlalchemy\util\langhelpers.py", line 754, in __get__
obj.__dict__[self.__name__] = result = self.fget(obj)
File "C:\Users\Music\mailtesterV2\lib\site-packages\sqlalchemy\orm\instrumentation.py", line 177, in _state_constructor
self.dispatch.first_init(self, self.class_)
File "C:\Users\Music\mailtesterV2\lib\site-packages\sqlalchemy\event\attr.py", line 256, in __call__
fn(*args, **kw)
File "C:\Users\Music\mailtesterV2\lib\site-packages\sqlalchemy\orm\mapper.py", line 2872, in _event_on_first_init
configure_mappers()
File "C:\Users\Music\mailtesterV2\lib\site-packages\sqlalchemy\orm\mapper.py", line 2768, in configure_mappers
mapper._post_configure_properties()
File "C:\Users\Music\mailtesterV2\lib\site-packages\sqlalchemy\orm\mapper.py", line 1708, in _post_configure_properties
prop.init()
File "C:\Users\Music\mailtesterV2\lib\site-packages\sqlalchemy\orm\interfaces.py", line 183, in init
self.do_init()
File "C:\Users\Music\mailtesterV2\lib\site-packages\sqlalchemy\orm\relationships.py", line 1632, in do_init
self._generate_backref()
File "C:\Users\Music\mailtesterV2\lib\site-packages\sqlalchemy\orm\relationships.py", line 1866, in _generate_backref
self._add_reverse_property(self.back_populates)
File "C:\Users\Music\mailtesterV2\lib\site-packages\sqlalchemy\orm\relationships.py", line 1574, in _add_reverse_property
other._reverse_property.add(self)
File "C:\Users\Music\mailtesterV2\lib\site-packages\sqlalchemy\util\langhelpers.py", line 840, in __getattr__
return self._fallback_getattr(key)
File "C:\Users\Music\mailtesterV2\lib\site-packages\sqlalchemy\util\langhelpers.py", line 818, in _fallback_getattr
raise AttributeError(key)
AttributeError: _reverse_property
マイコード：
from sqlalchemy import Column, ForeignKey, Integer, String, Boolean, DateTime
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import relationship, sessionmaker
from sqlalchemy import create_engine
engine = create_engine('sqlite:///:memory:', echo=True)
Session = sessionmaker(bind=engine)
Base = declarative_base()
class MailProvider(Base):
__tablename__ = 'mail_provider'
id = Column(Integer, primary_key=True)
service_provider = Column(String(250), nullable=False)
imap_server = Column(String(250))
imap_server_port = Column(Integer)
imap_server_ssl = Column(String(250))
imap_server_port_ssl = Column(Integer)
imap_server_use_tls = Column(Boolean)
smtp_server = Column(String(250))
smtp_server_port = Column(Integer)
smtp_server_ssl = Column(String(250))
smtp_server_port_ssl = Column(Integer)
smtp_server_use_tls = Column(Boolean)
class MailAccount(Base):
__tablename__ = "mail_account"
id = Column(Integer, primary_key=True)
email_address = Column(String(250), nullable=False)
imap_username = Column(String(250), nullable=False)
imap_password = Column(String(250), nullable=False)
smtp_username = Column(String(250), nullable=False)
smtp_password = Column(String(250), nullable=False)
provider_id = Column(Integer, ForeignKey('mail_provider.id'), nullable=False)
provider = relationship("MailProvider", back_populates="service_provider")
account_owner = Column(String(250), nullable=False)
class SentMail(Base):
__tablename__ = "sent_mail"
id = Column(Integer, primary_key=True)
mail_uuid = Column(String(36), nullable=False)
time_sent = Column(DateTime(timezone=True), nullable=False)
sent_from_id = Column(Integer, ForeignKey('mail_account.id'), nullable=False)
sent_from = relationship("MailAccount", back_populates="email_address")
sent_to = Column(String(250), nullable=False)
msg_subject = Column(String(250))
msg_body = Column(String)
send_status = Column(String(500))
class ReceivedMail(Base):
__tablename__ = "received_mail"
id = Column(Integer, primary_key=True)
sent_mail_id = Column(Integer, ForeignKey('sent_mail.id'), nullable=False)
sent_mail = relationship("SentMail", back_populates="mail_uuid")
time_received = Column(DateTime(timezone=True), nullable=False)
MailProvider.accounts = relationship("MailAccount", back_populates="provider", order_by="MailAccount.id")
MailAccount.mails_sent = relationship("SentMail", back_populates="mail_uuid", order_by="SentMail.time_sent")
SentMail.received_mails = relationship("RecievedMail", back_populates="received_time", order_by="RecievedMail.received_time")
Base.metadata.create_all(engine)
session = Session()
gmail = MailProvider(service_provider="gmail.com")
session.add(gmail)
session.commit()