“NoneType”对象没有属性“否定”[重复]

Question

我在尝试获取限制字段为 True 的所有 Url 时遇到错误。我已尝试删除迁移并创建新迁移，但仍然遇到相同的错误。

这些是已安装的依赖项：

• asgiref==3.4.1
• backports.zoneinfo==0.2.1
• Django==4.0
• django-cors-headers==3.10.1
• django-shell-plus==1.1.7
• djangorestframework==3.13.1
• djongo==1.3.6
• dnspython==2.1.0
• gunicorn==20.1.0
• pymongo==3.12.1
• python-dotenv==0.19.2
• pytz==2021.3
• sqlparse==0.2.4
• tzdata==2021.5

models.py：

class Urls(models.Model):
    _id = models.ObjectIdField()
    record_id = models.IntegerField(unique=True)
    hash = models.CharField(unique=True, max_length=1000)
    long_url = models.URLField()
    created_at = models.DateField(auto_now_add=True)
    expires_in = models.DurationField(default=timedelta(days=365*3))
    expires_on = models.DateField(null=True, blank=True)
    limited = models.BooleanField()
    exhausted = models.BooleanField()

查询：

Urls.objects.filter(limited=False)

错误：

Traceback (most recent call last):
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/query.py", line 857, in parse
    return handler(self, statement)
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/query.py", line 933, in _select
    return SelectQuery(self.db, self.connection_properties, sm, self._params)
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/query.py", line 116, in __init__
    super().__init__(*args)
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/query.py", line 62, in __init__
    self.parse()
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/query.py", line 152, in parse
    self.where = WhereConverter(self, statement)
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/converters.py", line 27, in __init__
    self.parse()
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/converters.py", line 119, in parse
    self.op = WhereOp(
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/operators.py", line 476, in __init__
    self.evaluate()
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/operators.py", line 465, in evaluate
    op.evaluate()
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/operators.py", line 258, in evaluate
    self.rhs.negate()
AttributeError: 'NoneType' object has no attribute 'negate'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/cursor.py", line 51, in execute
    self.result = Query(
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/query.py", line 784, in __init__
    self._query = self.parse()
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/sql2mongo/query.py", line 885, in parse
    raise exe from e
djongo.exceptions.SQLDecodeError:

        Keyword: None
        Sub SQL: None
        FAILED SQL: SELECT "short_urls"."_id", "short_urls"."record_id", "short_urls"."hash", "short_urls"."long_url", "short_urls"."created_at", "short_urls"."expires_in", "short_urls"."expires_on", "short_urls"."limited", "short_urls"."exhausted" FROM "short_urls" WHERE NOT "short_urls"."limited" LIMIT 21
        Params: ()
        Version: 1.3.6

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/backends/utils.py", line 85, in _execute
    return self.cursor.execute(sql, params)
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/cursor.py", line 59, in execute
    raise db_exe from e
djongo.database.DatabaseError

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/models/query.py", line 256, in __repr__
    data = list(self[:REPR_OUTPUT_SIZE + 1])
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/models/query.py", line 262, in __len__
    self._fetch_all()
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/models/query.py", line 1354, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/models/query.py", line 51, in __iter__
    results = compiler.execute_sql(chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size)
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1202, in execute_sql
    cursor.execute(sql, params)
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/backends/utils.py", line 99, in execute
    return super().execute(sql, params)
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/backends/utils.py", line 67, in execute
    return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/backends/utils.py", line 76, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/backends/utils.py", line 85, in _execute
    return self.cursor.execute(sql, params)
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/utils.py", line 90, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/django/db/backends/utils.py", line 85, in _execute
    return self.cursor.execute(sql, params)
  File "/mnt/c/Users/pranjal/Desktop/urlhash/env/lib/python3.8/site-packages/djongo/cursor.py", line 59, in execute
    raise db_exe from e
django.db.utils.DatabaseError

Answer 1

我需要查看你在哪里进行查询的 views.py，Urls.objects.filter(limited=False) 但首先，查询可能没有找到任何符合条件的 Urls 对象，limited=False，因此查询返回 None，它有没有属性。其次，我不熟悉否定。我没有在你的模型中看到它。也许如果我看到你进行查询的views.py，我会更好地理解。