Appengine错误对象没有属性'_key'

Question

我有一个GAE数据库实体，如下所示：

class Notification(db.Model):

    alert = db.StringProperty()
    type = db.StringProperty()
    status = db.StringProperty(default="unread", choices=set(["unread", "read"])) 
    created  = db.DateTimeProperty(auto_now_add=True)
    modified = db.DateTimeProperty(auto_now=True)
    entity = db.StringProperty()
    record = db.ReferenceProperty(model.RecordModel)
    actor = db.ReferenceProperty(model.Profile)
    account = db.ReferenceProperty(model.Account)

...我创建了一个像这样的实体：

notify = model2.Notification(account=account)
notify.alert = message
notify.type = "reminder"
notify.actor = actor
notify.record = record
notify.put() 

此调用引发错误 *'通知'对象没有属性'_key'*

nquery = db.Query(model2.Notification).filter('account =', self.session.account).order('-created')            
for n in nquery:
  try:
    _dict = {}
    _dict['serverID'] = str(n.key()) #- raises error! 

Answer 1

尝试：

nquery = Notification.all().filter('account =', self.session.account).order('-created') 

Answer 2

我想我已经明白了！我的Notification类中的“entity”属性在python appengine中引起某种命名冲突。更改名称将删除“错误对象没有属性'_key'”错误。去图！