Django 同步数据库错误

Question

我安装的应用程序中有 django.contrib.auth，大约 10 分钟前一切正常。我删除了现有的数据库，因为我在向南迁移时遇到了问题。当我尝试重建它时，出现错误。

错误：django.db.utils.DatabaseError：没有这样的表：auth_user

Traceback (most recent call last):
  File "manage.py", line 11, in <module>
    execute_manager(settings)
  File "/usr/lib/python2.7/site-packages/django/core/management/__init__.py", line 438, in execute_manager
    utility.execute()
  File "/usr/lib/python2.7/site-packages/django/core/management/__init__.py", line 379, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/lib/python2.7/site-packages/django/core/management/base.py", line 191, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/usr/lib/python2.7/site-packages/django/core/management/base.py", line 219, in execute
    self.validate()
  File "/usr/lib/python2.7/site-packages/django/core/management/base.py", line 249, in validate
    num_errors = get_validation_errors(s, app)
  File "/usr/lib/python2.7/site-packages/django/core/management/validation.py", line 35, in get_validation_errors
    for (app_name, error) in get_app_errors().items():
  File "/usr/lib/python2.7/site-packages/django/db/models/loading.py", line 146, in get_app_errors
    self._populate()
  File "/usr/lib/python2.7/site-packages/django/db/models/loading.py", line 61, in _populate
    self.load_app(app_name, True)
  File "/usr/lib/python2.7/site-packages/django/db/models/loading.py", line 78, in load_app
    models = import_module('.models', app_name)
  File "/usr/lib/python2.7/site-packages/django/utils/importlib.py", line 35, in import_module
    __import__(name)
  File "/home/bruk/workspace/hungryDroid/src/hungryDroid/Ingredient/models.py", line 22, in <module>
    class Ingredient(models.Model):
  File "/home/bruk/workspace/hungryDroid/src/hungryDroid/Ingredient/models.py", line 26, in Ingredient
    FKowner = models.ForeignKey(User, default=User.objects.get(pk=1).id)
  File "/usr/lib/python2.7/site-packages/django/db/models/manager.py", line 132, in get
    return self.get_query_set().get(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/django/db/models/query.py", line 342, in get
    num = len(clone)
  File "/usr/lib/python2.7/site-packages/django/db/models/query.py", line 80, in __len__
    self._result_cache = list(self.iterator())
  File "/usr/lib/python2.7/site-packages/django/db/models/query.py", line 271, in iterator
    for row in compiler.results_iter():
  File "/usr/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 677, in results_iter
    for rows in self.execute_sql(MULTI):
  File "/usr/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 732, in execute_sql
    cursor.execute(sql, params)
  File "/usr/lib/python2.7/site-packages/django/db/backends/util.py", line 15, in execute
    return self.cursor.execute(sql, params)
  File "/usr/lib/python2.7/site-packages/django/db/backends/sqlite3/base.py", line 200, in execute
    return Database.Cursor.execute(self, query, params)
**django.db.utils.DatabaseError: no such table: auth_user**

Answer 1

问题是您正在syncdb 过程中针对用户模型运行查询

  File "/home/bruk/workspace/hungryDroid/src/hungryDroid/Ingredient/models.py", line 26, in Ingredient
FKowner = models.ForeignKey(User, default=User.objects.get(pk=1).id)

（实际上是在字段声明期间，因此任何时候导入模块时，例如在此验证过程期间）。

这将确保在创建 auth_user 表之前执行 auth_user 查询。

使用默认用户获取功能的更安全方法是执行

def get_default_user():
    return User.objects.get(pk=1)

然后在字段声明中执行

FKowner = models.ForeignKey(User, default=get_default_user)

按照 模型字段引用 默认值可以是可调用的。请注意，如果您在其中使用 get_default_user() ，您会遇到同样的问题 - 然后它会立即执行，而不是按需执行。