我正在为一个新的Django项目设置表格（即，这些表格在数据库中还不存在）；Django版本为1.7，数据库后端为PostgreSQL。项目名称为crud。迁移尝试的结果如下：
python manage.py makemigrations crud
我正在尝试为一个新的 Django 项目设置数据表（也就是说，这些表在数据库中还不存在）；该项目使用的是 Django 版本 1.7，数据库后端是 PostgreSQL。项目名称为 crud。执行迁移命令的结果如下：
python manage.py makemigrations crud
Migrations for 'crud':
0001_initial.py:
- Create model AddressPoint
- Create model CrudPermission
- Create model CrudUser
- Create model LDAPGroup
- Create model LogEntry
- Add field ldap_groups to cruduser
- Alter unique_together for crudpermission (1 constraint(s))
python manage.py migrate crud
Operations to perform:
Apply all migrations: crud
Running migrations:
Applying crud.0001_initial...Traceback (most recent call last):
File "manage.py", line 18, in <module>
execute_from_command_line(sys.argv)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
utility.execute()
File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 377, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 288, in run_from_argv
self.execute(*args, **options.__dict__)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 338, in execute
output = self.handle(*args, **options)
File "/usr/local/lib/python2.7/dist-packages/django/core/management/commands/migrate.py", line 161, in handle
executor.migrate(targets, plan, fake=options.get("fake", False))
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 68, in migrate
self.apply_migration(migration, fake=fake)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 102, in apply_migration
migration.apply(project_state, schema_editor)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/migration.py", line 108, in apply
operation.database_forwards(self.app_label, schema_editor, project_state, new_state)
File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/operations/models.py", line 36, in database_forwards
schema_editor.create_model(model)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/schema.py", line 262, in create_model
self.execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/schema.py", line 103, in execute
cursor.execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/utils.py", line 82, in execute
return super(CursorDebugWrapper, self).execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/utils.py", line 66, in execute
return self.cursor.execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/utils.py", line 94, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/utils.py", line 66, in execute
return self.cursor.execute(sql, params)
django.db.utils.ProgrammingError: relation "crud_crudpermission" already exists
迁移文件的一些亮点：
dependencies = [
('auth', '0001_initial'),
('contenttypes', '0001_initial'),
]
migrations.CreateModel(
name='CrudPermission',
fields=[
('id', models.AutoField(verbose_name='ID', serialize=False, auto_created=True, primary_key=True)),
('_created_by', models.CharField(default=b'', max_length=64, null=True, editable=False, blank=True)),
('_last_updated_by', models.CharField(default=b'', max_length=64, null=True, editable=False, blank=True)),
('_created', models.DateTimeField(null=True, editable=False, blank=True)),
('_last_updated', models.DateTimeField(null=True, editable=False, blank=True)),
('domain', models.CharField(max_length=32, choices=[(b'town', b'Town'), (b'boe', b'BOE'), (b'police', b'Police')])),
('ldap_group', models.CharField(max_length=128, verbose_name=b'LDAP group')),
('can_add', models.BooleanField(default=False, verbose_name=b'add')),
('can_change', models.BooleanField(default=False, verbose_name=b'change')),
('restrict_change_to_own', models.BooleanField(default=False)),
('can_delete', models.BooleanField(default=False, verbose_name=b'delete')),
('restrict_delete_to_own', models.BooleanField(default=False)),
('models', models.ManyToManyField(to='contenttypes.ContentType', null=True, blank=True)),
],
options={
'verbose_name': 'CRUD permission',
},
bases=(models.Model,),
),
migrations.AlterUniqueTogether(
name='crudpermission',
unique_together=set([('ldap_group', 'can_add', 'can_change', 'can_delete', 'domain')]),
)
这个 CRUD 应用程序本身没有实际用途，但我在另一个应用程序中使用它，所以当我尝试从该应用程序迁移时，会触发上述问题。
我在网上找到了其他类似问题的例子，但他们的情况似乎都不适用于我的情况，因为：
- 这个问题影响整个关系，而不仅仅是一个列。
- 我没有使用多重继承。
接下来我应该在哪里查找潜在问题？
syncdb命令？如果是的话，这已经在数据库中创建了表格，所以这个迁移正在尝试重新创建。要跳过它，请运行python manage.py migrate --fake命令。 - Timmy O'Mahony