Question

我第一次尝试使用Django，但是从模型中查询时遇到了一些麻烦。

这是我的模特：

class User(models.Model):
    user = models.CharField(max_length=128, primary_key=True)
    password = models.CharField(max_length=128)
    count = models.IntegerField(default=1)

当我运行$> python manage.py sql users时，我得到：

BEGIN;
CREATE TABLE "users_user" (
    "user" varchar(128) NOT NULL PRIMARY KEY,
    "password" varchar(128) NOT NULL,
    "count" integer NOT NULL
)
;

当我通过$> python manage.py shell启动交互式shell时，我在尝试检索用户对象时收到错误。我知道没有，但它应该返回一个空列表。

$> python manage.py shell
Python 2.7.2 (default, Oct 11 2012, 20:14:37) 
[GCC 4.2.1 Compatible Apple Clang 4.0 (tags/Apple/clang-418.0.60)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from users.models import User
>>> User.objects.all()
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/Library/Python/2.7/site-packages/django/db/models/query.py", line 71, in __repr__
    data = list(self[:REPR_OUTPUT_SIZE + 1])
  File "/Library/Python/2.7/site-packages/django/db/models/query.py", line 96, in __iter__
    self._fetch_all()
  File "/Library/Python/2.7/site-packages/django/db/models/query.py", line 854, in _fetch_all
    self._result_cache = list(self.iterator())
  File "/Library/Python/2.7/site-packages/django/db/models/query.py", line 220, in iterator
    for row in compiler.results_iter():
  File "/Library/Python/2.7/site-packages/django/db/models/sql/compiler.py", line 709, in results_iter
    for rows in self.execute_sql(MULTI):
  File "/Library/Python/2.7/site-packages/django/db/models/sql/compiler.py", line 782, in execute_sql
    cursor.execute(sql, params)
  File "/Library/Python/2.7/site-packages/django/db/backends/util.py", line 69, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/Library/Python/2.7/site-packages/django/db/backends/util.py", line 53, in execute
    return self.cursor.execute(sql, params)
  File "/Library/Python/2.7/site-packages/django/db/utils.py", line 99, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/Library/Python/2.7/site-packages/django/db/backends/util.py", line 53, in execute
    return self.cursor.execute(sql, params)
  File "/Library/Python/2.7/site-packages/django/db/backends/sqlite3/base.py", line 450, in execute
    return Database.Cursor.execute(self, query, params)
OperationalError: no such column: users_user.user
>>>

在致电>>> User.objects.all()后（通过>>> from users.models import User导入后），我收到错误消息：

'OperationalError：没有这样的列：users_user.user'

如果在我运行“$> python manage.py sql users”时显示该列，该怎么办？

Answer 1

manage.py sql向您展示如果您从头开始创建表，将运行SQL 。并且syncdb不会修改现有表。

您需要删除表并再次运行syncdb。将来，请使用South。

Answer 2

我遇到了同样的问题并修复了：

class Email(models.Model):
    name = models.CharField(max_length=200)
    email = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published')

运行：

python manage.py sql emails

我得到了：

BEGIN; CREATE TABLE "emails_email" (
       "id" integer NOT NULL PRIMARY KEY,
       "name" varchar(200) NOT NULL,
       "email" varchar(200) NOT NULL,
       "pub_date" datetime NOT NULL ) ;

COMMIT;

所以Django已经创建了一个主键，我们不需要创建一个主键，或者似乎我们不应该创建一个主键。

OperationalError：没有这样的列 - 当列存在时发生

2 个答案: