Question

我希望能够为这样的事件添加被邀请者：

e = events.get(1)
u = users.get(1)
e.invitees.append(u)

然后在我的服务层中，我希望能够拥有如下功能：

def add_invitee(self, event, user):
    if user in self.get(event).invitees:
        raise OroposError(u'User already invited')
    event.invitees.append(user)
    return self.save(event), user

当我尝试这个时，会发生一些事情。当我尝试使用我的功能时，我收到此错误：

InterfaceError：（InterfaceError）错误绑定参数0 - 可能不支持的类型。 u'SELECT events.id AS events_id，events.user_id AS events_user_id，events.event_name AS events_event_name， events.event_mesg AS events_event_mesg，events.start_date AS events_start_date，events.end_date AS events_end_date， events.event_status AS events_event_status，events.rsvp AS events_rsvp，events.created AS events_created \ nFROM events \ nWHERE events.id =？' （，）

当我尝试e.invitees.append（u）时，我收到此错误：

  File "/Users/f/.virtualenvs/Oropos/lib/python2.7/site-packages/sqlalchemy/orm/collections.py", line 1057, in append
    item = __set(self, item, _sa_initiator)
  File "/Users/f/.virtualenvs/Oropos/lib/python2.7/site-packages/sqlalchemy/orm/collections.py", line 1029, in __set
    item = getattr(executor, 'fire_append_event')(item, _sa_initiator)
  File "/Users/f/.virtualenvs/Oropos/lib/python2.7/site-packages/sqlalchemy/orm/collections.py", line 733, in fire_append_event
    item, initiator)
  File "/Users/f/.virtualenvs/Oropos/lib/python2.7/site-packages/sqlalchemy/orm/attributes.py", line 910, in fire_append_event
    value = fn(state, value, initiator or self)
  File "/Users/f/.virtualenvs/Oropos/lib/python2.7/site-packages/sqlalchemy/orm/attributes.py", line 1140, in emit_backref_from_collection_append_event
    child_impl = child_state.manager[key].impl
KeyError: 'event'

这让我困扰了一段时间。有什么建议？

以下是与我的问题相关的模型。

class EventJsonSerializer(JsonSerializer):
    pass


class Event(EventJsonSerializer, db.Model):
    __tablename__ = 'events'

    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('users.id'))
    event_name = db.Column(db.String(30))
    event_mesg = db.Column(db.Text)
    start_date = db.Column(db.Date)
    end_date = db.Column(db.Date)
    event_status = db.Column(db.Boolean)
    rsvp = db.Column(db.Date)
    created = db.Column(db.DateTime, default=get_current_time)

    invitees = db.relationship('Invite', backref=db.backref('event'))
    proposals = db.relationship('Proposal', backref=db.backref('event'))


class InviteJsonSerializer(JsonSerializer):
    pass


class Invite(InviteJsonSerializer, db.Model):
    __tablename__ = 'invites'

    id = db.Column(db.Integer, primary_key=True)
    created = db.Column(db.Date, default=get_current_time)
    user_id = db.Column(db.ForeignKey('users.id'))
    event_id = db.Column(db.ForeignKey('events.id'))

    user = db.relationship('User', foreign_keys='Invite.user_id', lazy='joined')


class ProposalJsonSerializer(JsonSerializer):
    pass


class Proposal(ProposalJsonSerializer, db.Model):
    __tablename__ = 'proposals'

    id = db.Column(db.Integer, primary_key=True)
    created = db.Column(db.Date, default=get_current_time)
    date = db.Column(db.Date)
    user_id = db.Column(db.ForeignKey('users.id'))
    event_id = db.Column(db.ForeignKey('events.id'))

Answer 1

如果我没弄错，你试图在User个实例列表中添加Invite个实例，你确定它是对的吗？

根据您的代码，e.invitees包含Invite个实例，这些实例的外键event_id指向Event实例e。如果您希望invitees表示与User表的多对多关系（由两个外键暗示），您可能需要将其变为association table }。另外，我敢说一个User只能有一个Invite到一个Event，这意味着这些字段应该与UniqueConstraint表参数相关联。 / p>

sqlalchemy检查对象是否在模型中

1 个答案: