Question

想知道是否有其他人在使用Django迁移时遇到令人沮丧的行为。我已经查看了SO上的几个相关帖子，但没有找到任何解决这个问题的具体内容。

这种情况一直在发生，它必须是一种常见的情况，所以我错过了什么？

我的情景：

列表项
我已经构建了一个Django应用程序，在本地计算机上使用sqlite进行迭代
我现在想要部署到生产Postgresql数据库（AWS或其他地方）
我设置了新数据库，将其添加到我的设置中，然后运行python manage.py migrate
我收到一条SQL错误，告诉我我的某个模型表不存在。咄！这就是我正在运行迁移的原因。
我最终不得不手工制作表格，做一些奇怪的事情，例如python manage.py migrate <app_name> --fake，这会产生包括simple_history

我确信必须有一个明显的答案 - 我应该怎么做才能在一个全新的，干净的数据库上设置数据库架构？

编辑：我收到错误的追溯：

当我在空白数据库上运行python manage.py migrate时，出现以下错误：

(banzai-platform-django) ➜  src git:(master) ✗ ./manage.py migrate
Traceback (most recent call last):
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/db/backends/utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
psycopg2.ProgrammingError: relation "events_event" does not exist
LINE 1: ...ents_event"."created", "events_event"."slug" FROM "events_ev...
                                                             ^


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

Traceback (most recent call last):
  File "./manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/core/management/__init__.py", line 363, in execute_from_command_line
    utility.execute()
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/core/management/__init__.py", line 355, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/core/management/base.py", line 283, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/core/management/base.py", line 327, in execute
    self.check()
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/core/management/base.py", line 359, in check
    include_deployment_checks=include_deployment_checks,
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/core/management/commands/migrate.py", line 62, in _run_checks
    issues.extend(super(Command, self)._run_checks(**kwargs))
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/core/management/base.py", line 346, in _run_checks
    return checks.run_checks(**kwargs)
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/core/checks/registry.py", line 81, in run_checks
    new_errors = check(app_configs=app_configs)
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/core/checks/urls.py", line 16, in check_url_config
    return check_resolver(resolver)
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/core/checks/urls.py", line 26, in check_resolver
    return check_method()
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/urls/resolvers.py", line 254, in check
    for pattern in self.url_patterns:
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/utils/functional.py", line 35, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/urls/resolvers.py", line 405, in url_patterns
    patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/utils/functional.py", line 35, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/urls/resolvers.py", line 398, in urlconf_module
    return import_module(self.urlconf_name)
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 978, in _gcd_import
  File "<frozen importlib._bootstrap>", line 961, in _find_and_load
  File "<frozen importlib._bootstrap>", line 950, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 655, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 205, in _call_with_frames_removed
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/src/banzai_platform/urls.py", line 67, in <module>
    url(r'^registrations/', include('registrations.urls')),
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/conf/urls/__init__.py", line 50, in include
    urlconf_module = import_module(urlconf_module)
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 978, in _gcd_import
  File "<frozen importlib._bootstrap>", line 961, in _find_and_load
  File "<frozen importlib._bootstrap>", line 950, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 655, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 678, in exec_module
  File "<frozen importlib._bootstrap>", line 205, in _call_with_frames_removed
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/src/registrations/urls.py", line 3, in <module>
    from .views import (
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/src/registrations/views.py", line 160, in <module>
    class ConfirmEventListView(ListView):
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/src/registrations/views.py", line 164, in ConfirmEventListView
    queryset = [obj for obj in events if obj.need_confirmation > 0]
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/db/models/query.py", line 250, in __iter__
    self._fetch_all()
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/db/models/query.py", line 1118, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/db/models/query.py", line 53, in __iter__
    results = compiler.execute_sql(chunked_fetch=self.chunked_fetch)
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/db/models/sql/compiler.py", line 894, in execute_sql
    raise original_exception
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/db/models/sql/compiler.py", line 884, in execute_sql
    cursor.execute(sql, params)
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/db/backends/utils.py", line 80, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/db/backends/utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/db/utils.py", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/utils/six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "/Users/joedavy/Dropbox/Apps/banzai-platform-django/lib/python3.6/site-packages/django/db/backends/utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
django.db.utils.ProgrammingError: relation "events_event" does not exist
LINE 1: ...ents_event"."created", "events_event"."slug" FROM "events_ev...

Answer 1

您的回溯显示您正在ConfirmEventListView内的类级别的查询集上运行列表解析。在类首次导入时执行类级别的任何操作;因此，在执行任何Django命令之前立即执行此查询，这是在迁移有机会运行之前。

您绝不能在此级别执行任何访问数据库的操作。（说实话，你根本不应该做这个列表理解，因为它返回的是一个列表而不是一个查询集;所以它不适用于分页或其他期望实际查询集的东西。但是，因为你的其余部分代码有效，我们可以假设这不是你的问题 - 但是。）

如果need_confirmation是字段，则您的查询集应该只定义为Event.objects.filter(need_confirmation__gt=0)。但是，如果它是一个模型方法，那么你应该在ConfirmEventListView上定义一个get_queryset()方法并在那里进行处理，而不是在类级别。

Django迁移失败了新的数据库

1 个答案: