Question

我收到了这个奇怪的错误，我说的很奇怪，因为我改变了一张不相关的表格。

我正在尝试查询我的tDevice表格，如下所示：

class TDevice(Base):
    __tablename__ = 'tDevice'

    ixDevice = Column(Integer, primary_key=True)
    ixDeviceType = Column(Integer, ForeignKey('tDeviceType.ixDeviceType'), nullable=False)
    ixSubStation = Column(Integer, ForeignKey('tSubStation.ixSubStation'), nullable=False)
    ixModel = Column(Integer, ForeignKey('tModel.ixModel'), nullable=True)
    ixParentDevice = Column(Integer, ForeignKey('tDevice.ixDevice'), nullable=True)
    sDeviceName = Column(Unicode(255), nullable=False)#added

    children = relationship('TDevice',
                        backref=backref('parent', remote_side=[ixDevice]))

    device_type = relationship('TDeviceType',
                           backref=backref('devices'))

    model = relationship('TModel',
                     backref=backref('devices'))

    sub_station = relationship('TSubStation',
                           backref=backref('devices'))

这就是我查询它的方式：

Device = DBSession.query(TDevice).filter(TDevice.ixDevice == device_id).one()

执行此行后，我收到错误：

ArgumentError: relationship 'report_type' expects a class or a mapper argument (received: <class 'sqlalchemy.sql.schema.Table'>)

我所做的唯一更改是在tReportTable中添加report_type关系现在看起来像这样：

class TReport(Base):
__tablename__ = 'tReport'

ixReport = Column(Integer, primary_key=True)
ixDevice = Column(Integer, ForeignKey('tDevice.ixDevice'), nullable=False)
ixJob = Column(Integer, ForeignKey('tJob.ixJob'), nullable=False)
ixReportType = Column(Integer, ForeignKey('tReportType.ixReportType'), nullable=False) # added

report_type = relationship('tReportType',
                           uselist=False,
                           backref=backref('report'))

device = relationship('TDevice',
                      uselist=False,
                      backref=backref('report'))

job = relationship('TJob',
                   uselist=False,
                   backref=backref('report'))

我还是SqlAlchemy的新手，所以如果我在迭代另一个表，我似乎无法看到如何添加该关系会导致此错误

Answer 1

对自己并不满意，因为这是一个如此愚蠢的错误，但这是我的罪魁祸首：

report_type = relationship('tReportType',
                           uselist=False,
                           backref=backref('report'))

应该是：

report_type = relationship('TReportType',
                           uselist=False,
                           backref=backref('report'))

大写T代替t，我应该引用类，而不是我的实际表名：'tReportType' - ＆gt; 'TReportType'

ArgumentError：relationship需要一个类或映射器参数

1 个答案: