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python - Django 迁移失败 'QuerySet' 对象没有属性 'objects'

问题描述

我有一组模型：

class DebugConf(models.Model):
    is_setup = models.BooleanField(default=False)
    debug_setup_date = models.DateTimeField()

    def __str__(self):
        return self.is_setup


class Currency(models.Model):
    currency_name = models.CharField(max_length=100)
    currency_value_in_dollars = models.FloatField()
    currency_value_in_dollars_date = models.DateTimeField()

    def __str__(self):
        return self.currency_name


class User(models.Model):
    user_name = models.CharField(max_length=200)
    user_pass = models.CharField(max_length=200)
    join_date = models.DateTimeField()

    def __str__(self):
        return self.user_name


class Transaction(models.Model):
    transaction_type = models.CharField(max_length=200)
    transaction_amount = models.FloatField()
    transaction_date = models.DateTimeField()
    transaction_currency = models.ForeignKey(Currency, on_delete=models.CASCADE)
    transaction_users = models.ForeignKey(User, on_delete=models.CASCADE)

    def __str__(self):
        return self.headline

一个项目“crypto”和一个嵌套在其中的应用程序“manage_crypto_currency”：

该应用程序的视图包含一些初始化代码：

视图.py：

if IS_DEBUG_MODE:
    print('[!!!INFO!!!] DEBUG MODE SET! USING GENERATED TABLES')
    init_debug_tables()

def init_debug_tables():
    # Check if debug table has already been initialized
    debug_conf = DebugConf.objects.all()
    if debug_conf.objects.exists():
        return

目前，数据库尚未初始化；运行时：

python manage.py makemigrations manage_crypto_currency

在根目录（项目目录）中：

我得到：

[!!!INFO!!!] DEBUG MODE SET! USING GENERATED TABLES
Traceback (most recent call last):
  File "manage.py", line 24, in <module>
    main()
  File "manage.py", line 20, in main
    execute_from_command_line(sys.argv)
  File "C:\projects\django\crypto-currency-board\venv\lib\site-packages\django\core\management\__init__.py", line 401, in execute_from_command_line
    utility.execute()
  File "C:\projects\django\crypto-currency-board\venv\lib\site-packages\django\core\management\__init__.py", line 395, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "C:\projects\django\crypto-currency-board\venv\lib\site-packages\django\core\management\base.py", line 330, in run_from_argv
    self.execute(*args, **cmd_options)
  File "C:\projects\django\crypto-currency-board\venv\lib\site-packages\django\core\management\base.py", line 368, in execute
    self.check()
  File "C:\projects\django\crypto-currency-board\venv\lib\site-packages\django\core\management\base.py", line 392, in check
    all_issues = checks.run_checks(
  File "C:\projects\django\crypto-currency-board\venv\lib\site-packages\django\core\checks\registry.py", line 70, in run_checks
    new_errors = check(app_configs=app_configs, databases=databases)
  File "C:\projects\django\crypto-currency-board\venv\lib\site-packages\django\core\checks\urls.py", line 13, in check_url_config
    return check_resolver(resolver)
  File "C:\projects\django\crypto-currency-board\venv\lib\site-packages\django\core\checks\urls.py", line 23, in check_resolver
    return check_method()
  File "C:\projects\django\crypto-currency-board\venv\lib\site-packages\django\urls\resolvers.py", line 408, in check
    for pattern in self.url_patterns:
  File "C:\projects\django\crypto-currency-board\venv\lib\site-packages\django\utils\functional.py", line 48, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "C:\projects\django\crypto-currency-board\venv\lib\site-packages\django\urls\resolvers.py", line 589, in url_patterns
    patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
  File "C:\projects\django\crypto-currency-board\venv\lib\site-packages\django\utils\functional.py", line 48, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "C:\projects\django\crypto-currency-board\venv\lib\site-packages\django\urls\resolvers.py", line 582, in urlconf_module
    return import_module(self.urlconf_name)
  File "C:\Users\msebi\AppData\Local\Programs\Python\Python38-32\lib\importlib\__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 783, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "C:\projects\django\crypto-currency-board\crypto\crypto\urls.py", line 21, in <module>
    path('', include('manage_crypto_currency.urls')),
  File "C:\projects\django\crypto-currency-board\venv\lib\site-packages\django\urls\conf.py", line 34, in include
    urlconf_module = import_module(urlconf_module)
  File "C:\Users\msebi\AppData\Local\Programs\Python\Python38-32\lib\importlib\__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 783, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "C:\projects\django\crypto-currency-board\crypto\manage_crypto_currency\urls.py", line 5, in <module>
    from . import views
  File "C:\projects\django\crypto-currency-board\crypto\manage_crypto_currency\views.py", line 24, in <module>
    init_debug_tables()
  File "C:\projects\django\crypto-currency-board\crypto\manage_crypto_currency\setup_test_db\setup_debug_tables.py", line 14, in init_debug_tables
    if debug_conf.objects.exists():
AttributeError: 'QuerySet' object has no attribute 'objects'

该行：

[!!!INFO!!!] DEBUG MODE SET! USING GENERATED TABLES

在视图中。显然，迁移工具感觉需要执行views.py。为什么在地球上，我不知道。是否有可能使 makemigrations 不执行它不应该执行的代码，例如，在未初始化数据库的情况下只创建模型？

编辑

答案没有回答为什么 migrate 运行 views.py （我也不知道），但注释掉：

# if IS_DEBUG_MODE:
#     print('[!!!INFO!!!] DEBUG MODE SET! USING GENERATED TABLES')
#     init_debug_tables()

导致成功迁移。有没有更简单的方法来解决它？（取消）评论很丑陋。

标签： pythonpython-3.xdjango

解决方案

你不需要使用调用objectsaQuerySet

def init_debug_tables():
    # Check if debug table has already been initialized
    debug_conf = DebugConf.objects.all()
    if debug_conf.exists(): # instead of `debug_conf.objects.exists()`
        return

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