AttributeError: 'InstrumentedList' 对象没有属性 [英] AttributeError: 'InstrumentedList' object has no attribute

问题描述

我有这些表格:

class Thing(Base):
    __tablename__ = 'thing'
    id = Column(Integer, primary_key=True)

class User(Base):
    __tablename__ = 'user'
    id = Column(Integer, primary_key=True)

class Voteinfo(Base):
    __tablename__ = 'voteinfo'
    thing_id = Column(Integer, ForeignKey('thing.id'), primary_key=True)
    thing = relationship('Thing', backref='voteinfo')
    upvotes = Column(Integer)
    downvotes = Column(Integer)

    def __init__(self, thing)
        self.thing = thing

class VoteThing(Base):
    __tablename__ = 'votething'
    id = Column(Integer, primary_key=True)
    voter_id = Column(Integer, ForeignKey('voter.id'))
    voter = relationship('Voter', backref='votescast')
    thing_id = Column(Integer, ForeignKey('thing.id'))
    thing = relationship('Thing', backref='votesreceived')
    value = Column(Boolean)

    def __init__(self, voter, thing, value):
        if value is True:
            thing.voteinfo.upvotes += 1
        else:
            thing.voteinfo.downvotes += 1

当我尝试运行此程序时，我在if value is True"子句中收到此错误代码:

When I try to run this, I get this error code in the "if value is True" clause:

AttributeError: 'InstrumentedList' object has no attribute 'upvotes'

我尝试为 Voteinfo 提供自己的唯一 ID，并将 uselist=False 添加到关系中.我尝试将与事物的关系从 VoteThing 替换为 Voteinfo，但这也无济于事.我不知道 InstrumentedList 是什么.这是怎么回事?

I've tried giving Voteinfo its own unique ID and adding uselist=False to the relationship. I've tried replacing the relationship to thing from VoteThing to Voteinfo, but that didn't help either. I don't know what an InstrumentedList is. What is going on?

推荐答案

如文档中所述，此处:https://docs.sqlalchemy.org/en/latest/orm/basic_relationships.html#one-to-one，你必须添加 uselist=False 不到关系，但到反向引用.

As explained in the documentation, here : https://docs.sqlalchemy.org/en/latest/orm/basic_relationships.html#one-to-one, you have to add uselist=False not to the relationship, but to the backref.

thing = relationship('Thing', backref=backref('voteinfo', uselist=False))

这篇关于AttributeError: 'InstrumentedList' 对象没有属性的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！