Question

最初我的模型看起来像这样：

from __future__ import unicode_literals
from django.template.defaultfilters import slugify
from django.contrib.auth.models import User
from django.db import models
from datetime import datetime
class blogpost(models.Model):
    title = models.CharField(max_length = 200)
    body = models.TextField()
    createdon = models.DateTimeField(auto_now_add=True)
    slug = models.SlugField(unique=True)
    author = models.ForeignKey(User)

我应用了makemigrations，然后迁移到此模型。现在，我想从这个模型中删除字段slug。我删除它然后应用makemigrations。

^C(mysite)shivam@shivam-HP-Pavilion-15-Notebook-PC:~/Python/django/mysite/mysite$ python manage.py makemigrations
Migrations for 'blog':
  0003_remove_blogpost_slug.py:
    - Remove field slug from blogpost

但是现在当我申请迁移时，它会给我一个错误。

Operations to perform:
  Apply all migrations: admin, blog, contenttypes, auth, sessions
Running migrations:
  Rendering model states... DONE
  Applying blog.0003_remove_blogpost_slug...Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 350, in execute_from_command_line
    utility.execute()
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 342, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/django/core/management/base.py", line 348, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/django/core/management/base.py", line 399, in execute
    output = self.handle(*args, **options)
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/django/core/management/commands/migrate.py", line 200, in handle
    executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial)
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/django/db/migrations/executor.py", line 92, in migrate
    self._migrate_all_forwards(plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/django/db/migrations/executor.py", line 121, in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/django/db/migrations/executor.py", line 198, in apply_migration
    state = migration.apply(state, schema_editor)
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/django/db/migrations/migration.py", line 123, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/django/db/migrations/operations/fields.py", line 121, in database_forwards
    schema_editor.remove_field(from_model, from_model._meta.get_field(self.name))
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/django/db/backends/base/schema.py", line 438, in remove_field
    self.execute(sql)
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/django/db/backends/base/schema.py", line 110, in execute
    cursor.execute(sql, params)
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/django/db/backends/utils.py", line 79, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/django/db/utils.py", line 95, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/django/db/backends/mysql/base.py", line 112, in execute
    return self.cursor.execute(query, args)
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/MySQLdb/cursors.py", line 205, in execute
    self.errorhandler(self, exc, value)
  File "/home/shivam/Python/django/mysite/local/lib/python2.7/site-packages/MySQLdb/connections.py", line 36, in defaulterrorhandler
    raise errorclass, errorvalue
django.db.utils.OperationalError: (1091, "Can't DROP 'slug'; check that column/key exists")

如何移除slu field字段？

在django中更新模型

0 个答案: