Django 1.8 - 字段错误 : Cannot resolve keyword into field

Question

我最近从 Django 1.6 升级到 Django 1.8。当我这样做时，我发现我无法再通过外键关系进行查找，如下所述: https://docs.djangoproject.com/en/1.8/topics/db/queries/#lookups-that-span-relationships .

系统设置为有两个项目使用相同的数据库。 (不是我的想法，但我现在不想改变。)最初创建和迁移模型的项目在升级后工作得很好，但另一个项目却不行。每个模型文件都是相同的。

模型.py:

class Site(models.Model):
    name = models.CharField(max_length=255)

    class Meta:
        app_label = 'project1'

class Page(models.Model):
    title = models.CharField(max_length=255)
    site = models.ForeignKey('Site')

    class Meta:
        app_label = 'project1'

来自 Django Shell 的错误回溯:

>>> x = models.Site.objects.filter(page__id=1000)
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/home/user_name/project2/venv/local/lib/python2.7/site-packages/django/db/models/manager.py", line 127, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/home/user_name/project2/venv/local/lib/python2.7/site-packages/django/db/models/query.py", line 679, in filter
    return self._filter_or_exclude(False, *args, **kwargs)
  File "/home/user_name/project2/venv/local/lib/python2.7/site-packages/django/db/models/query.py", line 697, in _filter_or_exclude
    clone.query.add_q(Q(*args, **kwargs))
  File "/home/user_name/project2/venv/local/lib/python2.7/site-packages/django/db/models/sql/query.py", line 1314, in add_q
    clause, require_inner = self._add_q(where_part, self.used_aliases)
  File "/home/user_name/project2/venv/local/lib/python2.7/site-packages/django/db/models/sql/query.py", line 1342, in _add_q
    allow_joins=allow_joins, split_subq=split_subq,
  File "/home/user_name/project2/venv/local/lib/python2.7/site-packages/django/db/models/sql/query.py", line 1154, in build_filter
    lookups, parts, reffed_expression = self.solve_lookup_type(arg)
  File "/home/user_name/project2/venv/local/lib/python2.7/site-packages/django/db/models/sql/query.py", line 1035, in solve_lookup_type
    _, field, _, lookup_parts = self.names_to_path(lookup_splitted, self.get_meta())
  File "/home/user_name/project2/venv/local/lib/python2.7/site-packages/django/db/models/sql/query.py", line 1401, in names_to_path
    "Choices are: %s" % (name, ", ".join(available)))
FieldError: Cannot resolve keyword 'page' into field. Choices are: name, id

在第一个项目中，相同的查询按预期工作:

>>> x = models.Site.objects.filter(page__id=1000)
[<Site: http://stackoverflow.com>]

Answer 1

如果你设置 related_name 会怎么样？在 `ForeignKey 上？

class Page(models.Model):
    site = models.ForeignKey('Site', related_name="pages")  # Note the related_name here

我在另一个项目上尝试过它，它按预期工作:

>>> Site.objects.filter(pages__pk=42)
[<Site: http://stackoverflow.com>]

如果你没有设置related_name ，我认为默认是<model>_set 。所以应该是page_set .