保存创建者、更新者和删除者信息

Question

我正在尝试将有关创建、更新或删除记录的信息保存在每个表中。

目前我有以下：

class User(Base):
    __tablename__ = "user"

    id = Column(UUID, primary_key=True, index=True)
    
    civil_title = Column(Enum(EnumTitle))
    lastname = Column(String, index=True)
    firstname = Column(String)
    type = Column(Enum(EnumTypeUser))

    hashed_password = Column(String, nullable=False)
    is_active = Column(Boolean(), default=True)
    is_superuser = Column(Boolean(), default=False)

    created_at = Column(TIMESTAMP(timezone=False),server_default=func.now(), nullable=False)
    created_by = Column(UUID, ForeignKey("user.id"))
    created_by_rl = relationship("User", foreign_keys=[created_by])
    updated_at = Column(DateTime)
    updated_by = Column(UUID, ForeignKey("user.id"))
    updated_by_rl = relationship("User", foreign_keys=[updated_by])
    deleted_at = Column(DateTime)
    deleted_by = Column(UUID, ForeignKey("user.id"))
    deleted_by_rl = relationship("User", foreign_keys=[deleted_by])
    practice_id = Column(UUID, ForeignKey("practice.id"))
    practice = relationship("Practice", foreign_keys=[practice_id], back_populates="employees")

    address_id =  Column(UUID, ForeignKey("user_address.id"))
    address = relationship("UserAddress",foreign_keys=[address_id], back_populates="users")
    # items = relationship("Item", back_populates="owner")

    contacts = relationship("UserContactDetail", back_populates="user")

    schedules = relationship("Schedule", back_populates="user")

    __mapper_args__ = {
        "polymorphic_identity":"user",
        "polymorphic_on":type
    }

和

class UserAddress(Base):
    __tablename__ = "user_address"

    id = Column(UUID, primary_key=True, index=True)
    
    street = Column(String)
    streetnumber = Column(String)
    town = Column(String)
    cp = Column(Integer)

    created_at = Column(TIMESTAMP(timezone=False),server_default=func.now(), nullable=False)
    created_by = Column(UUID, ForeignKey("user.id"))
    created_by_rl = relationship("User", foreign_keys=[created_by])
    updated_at = Column(DateTime)
    updated_by = Column(UUID, ForeignKey("user.id"))
    updated_by_rl = relationship("User", foreign_keys=[updated_by])
    deleted_at = Column(DateTime)
    deleted_by = Column(UUID, ForeignKey("user.id"))
    deleted_by_rl = relationship("User", foreign_keys=[deleted_by])

    users = relationship("User", back_populates="address")

我遇到以下错误：

sqlalchemy.exc.AmbiguousForeignKeysError: Can't determine join between 'user_address' and 'user'; tables have more than one foreign key constraint relationship between them. Please specify the 'onclause' of this join explicitly.

如何确保不会发生此错误？ 做这样的事情是个好习惯吗？

Answer 1

您正在向所有这些列添加错误定义的关系，这就是该错误的原因。为了解决你的问题，我会尝试这样的事情：

class TrackTimeMixin:

    created_at = Column(DateTime, server_default=func.now())

    updated_at = Column(DateTime, server_default=func.now(), onupdate=datetime.now)

class SoftDeleteMixin:
    deleted_at = Column(DateTime, nullable=True)

    def soft_delete(self):
        self.deleted_at = datetime.now()


class User(Base, TrackTimeMixin, SoftDeleteMixin):
    """define other columns"""

class UserAddress(Base, TrackTimeMixin, SoftDeleteMixin):
    """define other columns"""

TrackTimeMixin 用于created_at 和updated_at 列，它应该 自动工作。

SoftDeleteMixin 添加deleted_at 列，您需要添加更多逻辑才能使其正常工作。

我有意将其拆分为 2 个 mixin，因为对于其他一些模型，您可能只想使用其中一个或不使用其中一个。所以现在，当你想删除一个用户时，你而不是这样做：

session.delete(user)
session.commit()

你实际上会这样做：

user.soft_delete()
session.commit()

您还需要一个逻辑来获取未删除的用户，但从这一点开始应该很容易实现。