错误：psycopg2.IntegrityError:列“modified”在社交身份验证模块中包含空值？

Question

我正在使用Django 1.9开发一个代码库，我正忙于准备升级到1.10

从python social auth迁移到python social auth应用程序django后，我遇到了一个问题。我使用了找到here的步骤

更新设置和url文件后，我遇到以下错误。有人知道我该怎么做吗

Running migrations:
  Rendering model states... DONE
  Applying social_django.0006_partial... OK
  Applying social_django.0007_code_timestamp... OK
  Applying social_django.0008_partial_timestamp... OK
  Applying social_django.0009_auto_20191118_0520...Traceback (most recent call last):
  File "/home/brendan/venvs/social/lib/python3.6/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
psycopg2.IntegrityError: column "modified" contains null values


The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/home/brendan/venvs/social/lib/python3.6/site-packages/django/core/management/__init__.py", line 353, in execute_from_command_line
    utility.execute()
  File "/home/brendan/venvs/social/lib/python3.6/site-packages/django/core/management/__init__.py", line 345, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/brendan/venvs/social/lib/python3.6/site-packages/django/core/management/base.py", line 348, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/home/brendan/venvs/social/lib/python3.6/site-packages/django/core/management/base.py", line 399, in execute
    output = self.handle(*args, **options)
  File "/home/brendan/venvs/social/lib/python3.6/site-packages/django/core/management/commands/migrate.py", line 200, in handle
    executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial)
  File "/home/brendan/venvs/social/lib/python3.6/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/brendan/venvs/social/lib/python3.6/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/brendan/venvs/social/lib/python3.6/site-packages/django/db/migrations/executor.py", line 198, in apply_migration
    state = migration.apply(state, schema_editor)
  File "/home/brendan/venvs/social/lib/python3.6/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/brendan/venvs/social/lib/python3.6/site-packages/django/db/migrations/operations/fields.py", line 62, in database_forwards
    field,
  File "/home/brendan/venvs/social/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 396, in add_field
    self.execute(sql, params)
  File "/home/brendan/venvs/social/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 110, in execute
    cursor.execute(sql, params)
  File "/home/brendan/venvs/social/lib/python3.6/site-packages/django/db/backends/utils.py", line 79, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/home/brendan/venvs/social/lib/python3.6/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/home/brendan/venvs/social/lib/python3.6/site-packages/django/db/utils.py", line 95, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/home/brendan/venvs/social/lib/python3.6/site-packages/django/utils/six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "/home/brendan/venvs/social/lib/python3.6/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
django.db.utils.IntegrityError: column "modified" contains null values

Answer 1

我遇到了完全相同的问题。（{}->；在{}->；{}->；{}->；在{}->；{}={}中设置{}）

起初，我认为这是模型和迁移文件中的更改之间的冲突。例如，从这里开始：

django.db.utils.IntegrityError: column "venue_city" contains null values

Looks like you added null=True after created migration file

但是，这看起来并不正确，因为/usr/local/lib/python2.7/site-packages/social_django/models.py不包括null=True：

    created = models.DateTimeField(auto_now_add=True)
    modified = models.DateTimeField(auto_now=True)

相反，我怀疑问题在于创建列时更新现有行的默认值为null，这会立即发生冲突。这里讨论了这一点：

Django Migrations Add Field with Default as Function of Model

我通过将null=True添加到/usr/local/lib/python2.7/site-packages/social_django/migrations/0009_auto_20191118_0520.py（或安装了social_django的任何地方）的modified字段并重新运行迁移来克服这个错误

        migrations.AddField(
            model_name='usersocialauth',
            name='created',
            field=models.DateTimeField(auto_now_add=True, default=django.utils.timezone.now),
            preserve_default=False,
        ),
        migrations.AddField(
            model_name='usersocialauth',
            name='modified',
-           field=models.DateTimeField(auto_now=True),
+           field=models.DateTimeField(auto_now=True, null=True),
        ),

更好的方法可能是像对created字段所做的那样设置default=django.utils.timezone.now