Django 单元测试 - 无法创建 django_migrations table

Question

我正在尝试使用 manage.py test 编写一些单元测试并运行它们，但由于某些原因脚本无法创建 django_migrations table。

这是完整的错误：

Creating test database for alias 'default'...
Traceback (most recent call last):
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\backends\utils.py", line 83, in _execute
    return self.cursor.execute(sql)
psycopg2.ProgrammingError: no schema has been selected to create in
LINE 1: CREATE TABLE "django_migrations" ("id" serial NOT NULL PRIMA...
                     ^


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

Traceback (most recent call last):
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\migrations\recorder.py", line 55, in ensure_schema
    editor.create_model(self.Migration)
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\backends\base\schema.py", line 298, in create_model
    self.execute(sql, params or None)
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\backends\base\schema.py", line 117, in execute
    cursor.execute(sql, params)
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\backends\utils.py", line 68, in execute
    return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\backends\utils.py", line 77, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\backends\utils.py", line 85, in _execute
    return self.cursor.execute(sql, params)
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\utils.py", line 89, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\backends\utils.py", line 83, in _execute
    return self.cursor.execute(sql)
django.db.utils.ProgrammingError: no schema has been selected to create in
LINE 1: CREATE TABLE "django_migrations" ("id" serial NOT NULL PRIMA...
                     ^


During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "manage.py", line 15, in <module>
    execute_from_command_line(sys.argv)
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\core\management\__init__.py", line 371, in execute_from_command_line
    utility.execute()
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\core\management\__init__.py", line 365, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\core\management\commands\test.py", line 26, in run_from_argv
    super().run_from_argv(argv)
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\core\management\base.py", line 288, in run_from_argv
    self.execute(*args, **cmd_options)
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\core\management\base.py", line 335, in execute
    output = self.handle(*args, **options)
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\core\management\commands\test.py", line 59, in handle
    failures = test_runner.run_tests(test_labels)
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\test\runner.py", line 601, in run_tests
    old_config = self.setup_databases()
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\test\runner.py", line 548, in setup_databases
    self.parallel, **kwargs
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\test\utils.py", line 176, in setup_databases
    serialize=connection.settings_dict.get('TEST', {}).get('SERIALIZE', True),
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\backends\base\creation.py", line 68, in create_test_db
    run_syncdb=True,
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\core\management\__init__.py", line 141, in call_command
    return command.execute(*args, **defaults)
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\core\management\base.py", line 335, in execute
    output = self.handle(*args, **options)
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\core\management\commands\migrate.py", line 200, in handle
    fake_initial=fake_initial,
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\migrations\executor.py", line 91, in migrate
    self.recorder.ensure_schema()
  File "C:\Program Files (x86)\Python36-32\lib\site-packages\django\db\migrations\recorder.py", line 57, in ensure_schema
    raise MigrationSchemaMissing("Unable to create the django_migrations table (%s)" % exc)
django.db.migrations.exceptions.MigrationSchemaMissing: Unable to create the django_migrations table (no schema has been selected to create in
LINE 1: CREATE TABLE "django_migrations" ("id" serial NOT NULL PRIMA...
                     ^
)

我试过运行宁这些 GRANT 建议的语句 here:

grant usage on schema public to <username>;  
grant create on schema public to <username>;

但我仍然收到相同的消息。有什么办法可以解决这个问题吗？可能是 search_path 问题？

更新

~ python manage.py makemigrations users
Migrations for 'users':
  users\migrations[=14=]01_initial.py
    - Create model MyUser

~ python manage.py migrate
Operations to perform:
  Apply all migrations: auth, contenttypes, sessions, users
Running migrations:
  No migrations to apply.

我在执行 migrate 之前尝试了 makemigrations（呃！），但我仍然遇到与以前相同的错误。迁移甚至得到应用了吗？我还应该提到我的 models.py 只有一个 model/table 而不是 Django 的 "managed"。

Bueller...Bueller...Beuller...有人吗？

Answer 1

我最近运行遇到了类似的问题，结果发现没有为试图创建对象的 user/role 定义默认架构。为了解决这个问题，我做了其中一个或两个（我不记得是哪一个）：

添加 search_path: ALTER ROLE <user_name> SET search_path TO schema1, schema2
使用 currentSchema 参数连接到数据库

Answer 2

我运行同样报错然后解决了。就我而言，我相信这是因为我将 Django 默认模式设置为 django，当运行 $ python manage.py test，测试函数试图将一些表迁移到数据库 test schema django，但是 schema django 还没有在那里创建。所以解决方案是 (1) 允许 Django 测试函数也在模式 public 中搜索，或者 (2) run unit test without a test database.

从这个问题的公认答案来看，我想我的情况与问题的不同。但我认为两者都是由于 Django 无法在搜索路径中找到模式造成的。因此我在这里发布了我的解决方案。希望对类似情况有所帮助。

(django-tally-QTYVOJb0) (python3.6) D:\github\django-tally>python manage.py test
Creating test database for alias 'default'...
Got an error creating the test database: database "test" already exists

Type 'yes' if you would like to try deleting the test database 'test', or 'no' to cancel: yes
Destroying old test database for alias 'default'...
Traceback (most recent call last):
  File "C:\Users\guido\.virtualenvs\django-tally-QTYVOJb0\lib\site-packages\django\db\backends\utils.py", line 84, in _execute
    return self.cursor.execute(sql)
psycopg2.errors.InvalidSchemaName: no schema has been selected to create in
LINE 1: CREATE TABLE "django_migrations" ("id" serial NOT NULL PRIMA...

对于解决方案（1）： settings.py中的数据库设置以前是这样的。

if 'RDS_HOSTNAME' in os.environ:
    DATABASES = {
        'default': {
            'ENGINE': 'django.db.backends.postgresql_psycopg2',
            'NAME': os.environ['RDS_DB_NAME'],
            'USER': os.environ['RDS_USERNAME'],
            'PASSWORD': os.environ['RDS_PASSWORD'],
            'HOST': os.environ['RDS_HOSTNAME'],
            'PORT': os.environ['RDS_PORT'],
            'OPTIONS': {
                'options': '-c search_path=django'
            },
            'TEST': {
                'NAME': 'test', # test database name
            },
        },
    }

现在看起来是这样的。我在搜索路径中添加了 public。

if 'RDS_HOSTNAME' in os.environ:
    DATABASES = {
        'default': {
            'ENGINE': 'django.db.backends.postgresql_psycopg2',
            'NAME': os.environ['RDS_DB_NAME'],
            'USER': os.environ['RDS_USERNAME'],
            'PASSWORD': os.environ['RDS_PASSWORD'],
            'HOST': os.environ['RDS_HOSTNAME'],
            'PORT': os.environ['RDS_PORT'],
            'OPTIONS': {
                'options': '-c search_path=django,public'
            },
            'TEST': {
                'NAME': 'test', # test database name
            },
        },
    }

Answer 3

对于同样的错误，我做了一些不同的事情，没什么不同，但我直接去了 psql 服务器（在我的例子中）。它发生在开发过程中。所以，我没有意识到可能的数据丢失。 Select 你的数据库。然后，创建架构。

CREATE SCHEMA public;
GRANT ALL ON SCHEMA public TO postgres;
GRANT ALL ON SCHEMA public TO public;

我从那里得到了答案。因为，我遇到了问题，因为我删除了所有表格。

Answer 4

我想现在回答太晚了，但对我来说有用的只是简单的遵循以下步骤：

1) open the pg admin application 
2)open the database you created
3)you will see schemas and then right click on it and create the schemas and named it as public then save.
4)then migrate the table from command line you will see migrations

Answer 5

这对我有用。

CREATE SCHEMA public;
GRANT ALL ON SCHEMA public TO postgres;
GRANT ALL ON SCHEMA public TO public;
GRANT ALL ON SCHEMA public TO <username>;

Django 单元测试 - 无法创建 django_migrations table

Django Unit Tests - Unable to create the django_migrations table

django

postgresql

django-unittest