Django'Key（field）=（）重复'

Question

此问题在here之前已被询问，但用于不同的场景。

我正在做一个Django/W 012项目。在某些时候，我不得不修改模型，并添加一些字段。

我意外地包括一个标志unique = True为一个新的领域。通过这种方式：

title = models.CharField(max_length=100, unique=True, blank=True, null=True, verbose_name=_('Category Title')) 

当进行迁移和迁移，它大叫此问题：

然后我意识到了错误，删除独特=真，离开它像这样：

title = models.CharField(max_length=100, blank=True, null=True, verbose_name=_('Category Title')) 

我做了迁移和迁移再次，期待这个问题消失。但是我得到同样的问题。

我该如何解决这个问题？

这是最后的迁移：

class Migration(migrations.Migration): 

    dependencies = [ 
     ('distributed', '0029_remove_blogcategory_title'), 
    ] 

    operations = [ 
     migrations.AddField(
      model_name='blogcategory', 
      name='title', 
      field=models.CharField(blank=True, max_length=100, null=True, verbose_name='Category Title'), 
     ), 
    ] 

这是跟踪：

Microsoft Windows [Versión 6.1.7600] 
Copyright (c) 2009 Microsoft Corporation. Reservados todos los derechos. 

C:\Windows\system32>cd C:/ 

C:\>cd distributed 

C:\distributed>cd distributed 

C:\distributed\distributed>python manage.py runserver 
Performing system checks... 

System check identified no issues (0 silenced). 

You have 6 unapplied migration(s). Your project may not work properly until you 
apply the migrations for app(s): distributed. 
Run 'python manage.py migrate' to apply them. 
April 26, 2017 - 12:40:45 
Django version 1.10.7, using settings 'genesis.settings.dev' 
Starting development server at http://127.0.0.1:8000/ 
Quit the server with CTRL-BREAK. 
^C 
C:\distributed\distributed>python manage.py migrate 
Operations to perform: 
    Apply all migrations: admin, auth, contenttypes, distributed, otp_static, otp_ 
totp, otp_yubikey, sessions, sites, taggit, two_factor, wagtailadmin, wagtailcor 
e, wagtaildocs, wagtailembeds, wagtailforms, wagtailimages, wagtailredirects, wa 
gtailsearch, wagtailusers 
Running migrations: 
    Applying distributed.0025_auto_20170425_1827...Traceback (most recent call las 
t): 
    File "manage.py", line 11, in <module> 
    execute_from_command_line(sys.argv) 
    File "C:\Python27\lib\site-packages\django\core\management\__init__.py", line 
367, in execute_from_command_line 
    utility.execute() 
    File "C:\Python27\lib\site-packages\django\core\management\__init__.py", line 
359, in execute 
    self.fetch_command(subcommand).run_from_argv(self.argv) 
    File "C:\Python27\lib\site-packages\django\core\management\base.py", line 294, 
in run_from_argv 
    self.execute(*args, **cmd_options) 
    File "C:\Python27\lib\site-packages\django\core\management\base.py", line 345, 
in execute 
    output = self.handle(*args, **options) 
    File "C:\Python27\lib\site-packages\django\core\management\commands\migrate.py 
", line 204, in handle 
    fake_initial=fake_initial, 
    File "C:\Python27\lib\site-packages\django\db\migrations\executor.py", line 11 
5, in migrate 
    state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_i 
nitial=fake_initial) 
    File "C:\Python27\lib\site-packages\django\db\migrations\executor.py", line 14 
5, in _migrate_all_forwards 
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_ 
initial) 
    File "C:\Python27\lib\site-packages\django\db\migrations\executor.py", line 24 
4, in apply_migration 
    state = migration.apply(state, schema_editor) 
    File "C:\Python27\lib\site-packages\django\db\migrations\migration.py", line 1 
29, in apply 
    operation.database_forwards(self.app_label, schema_editor, old_state, projec 
t_state) 
    File "C:\Python27\lib\site-packages\django\db\migrations\operations\fields.py" 
, line 84, in database_forwards 
    field, 
    File "C:\Python27\lib\site-packages\django\db\backends\postgresql\schema.py", 
line 21, in add_field 
    super(DatabaseSchemaEditor, self).add_field(model, field) 
    File "C:\Python27\lib\site-packages\django\db\backends\base\schema.py", line 4 
09, in add_field 
    self.execute(sql, params) 
    File "C:\Python27\lib\site-packages\django\db\backends\base\schema.py", line 1 
12, in execute 
    cursor.execute(sql, params) 
    File "C:\Python27\lib\site-packages\django\db\backends\utils.py", line 79, in 
execute 
    return super(CursorDebugWrapper, self).execute(sql, params) 
    File "C:\Python27\lib\site-packages\cachalot\monkey_patch.py", line 111, in in 
ner 
    out = original(cursor, sql, *args, **kwargs) 
    File "C:\Python27\lib\site-packages\django\db\backends\utils.py", line 64, in 
execute 
    return self.cursor.execute(sql, params) 
    File "C:\Python27\lib\site-packages\django\db\utils.py", line 94, in __exit__ 
    six.reraise(dj_exc_type, dj_exc_value, traceback) 
    File "C:\Python27\lib\site-packages\django\db\backends\utils.py", line 64, in 
execute 
    return self.cursor.execute(sql, params) 
django.db.utils.IntegrityError: could not create unique index "distributed_blogc 
ategory_title_key" 
DETAIL: Key (title)=() is duplicated. 


C:\distributed\distributed> 

Answer 1

回溯是告诉你发生的错误，当您尝试运行迁移0025

python manage.py showmigrations的输出表明迁移0025-0030尚未应用。

[X] 0022_auto_20170109_1620 
[X] 0023_auto_20170109_1621 
[X] 0024_auto_20170112_1933 
[ ] 0025_auto_20170425_1827 
[ ] 0026_auto_20170425_1829 
[ ] 0027_auto_20170425_1839 
[ ] 0028_auto_20170425_1840 
[ ] 0029_remove_blogcategory_title 
[ ] 0030_blogcategory_title 

因此，删除这些迁移应该是安全的（您可能希望备份它们以保证安全）。然后您可以重新运行makemigrations和migrate重新创建并运行新的迁移。