Question

我尝试从Django 1.6.7升级到1.7.1

然而，在我的本地virtualenv升级Django版本以及我自己的所有Django应用程序（新的migrate都有效）之后，我无法获得migrate easy_thumbnails app（版本2.2）工作。这个版本应该可以在Django 1.7中使用新的迁移系统（南方文档）正常工作（说明here）。

据我所知，原因是easy_thumbnails应用中的第二次迁移正在尝试重新创建迁移（源代码here）。

但很自然，由于这些代码是由包裹作者故意提供的，我担心自己会做错事。

任何想法是什么原因造成的？

完整堆栈跟踪：

./manage.py migrate easy_thumbnails --settings=[my.settings.module]
Operations to perform:
  Apply all migrations: easy_thumbnails
Running migrations:
  Applying easy_thumbnails.0002_thumbnaildimensions...Traceback (most recent call last):
  File "./manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
    utility.execute()
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 377, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/core/management/base.py", line 288, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/core/management/base.py", line 338, in execute
    output = self.handle(*args, **options)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/core/management/commands/migrate.py", line 160, in handle
    executor.migrate(targets, plan, fake=options.get("fake", False))
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/migrations/executor.py", line 63, in migrate
    self.apply_migration(migration, fake=fake)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/migrations/executor.py", line 97, in apply_migration
    migration.apply(project_state, schema_editor)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/migrations/migration.py", line 107, in apply
    operation.database_forwards(self.app_label, schema_editor, project_state, new_state)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/migrations/operations/models.py", line 36, in database_forwards
    schema_editor.create_model(model)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/backends/schema.py", line 263, in create_model
    self.execute(sql, params)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/backends/schema.py", line 99, in execute
    cursor.execute(sql, params)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/backends/utils.py", line 81, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/backends/utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/utils.py", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/usr/local/virtualenvs/fsenv/local/lib/python2.7/site-packages/django/db/backends/utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
django.db.utils.ProgrammingError: relation "easy_thumbnails_thumbnaildimensions" already exists

Answer 1

通过以下步骤解决了上述问题。

恢复虚拟环境
恢复到以前的代码版本（使用南迁移，而不是Django迁移）
使用以下命令恢复上次应用的easy_thumbnails迁移（迁移0016）：

python manage.py migrate easy_thumbnails 0015 --settings=[your.settings.module]
 - Soft matched migration 0015 to 0015_auto__del_unique_thumbnail_name_storage_hash__add_unique_thumbnail_sou.
Running migrations for easy_thumbnails:
 - Migrating backwards to just after 0015_auto__del_unique_thumbnail_name_storage_hash__add_unique_thumbnail_sou.
 < easy_thumbnails:0016_auto__add_thumbnaildimensions

在虚拟环境中恢复Django 1.7.1（使用pip install Django==1.7.1）
运行新的migrate;现在应该工作

Answer 2

实际上你可以在迁移之前删除表：

./manage.py dbshell

# in db console run:
DROP TABLE easy_thumbnails_thumbnaildimensions;

在Django中迁移easy_thumbnails从1.6.7升级到1.7.1

2 个答案: