类型错误：int() 参数必须是字符串、类似字节的对象或数字，而不是“datetime.datetime”

我试图为我的所有模型添加“created_at”字段，但收到以下错误...

TypeError: int() argument must be a string, a bytes-like object or a number, not 'datetime.datetime'

按照顺序，这是我的工作流程......

1）我把created_at = models.DateTimeField(auto_now_add=True)在我的模型中。
2）我跑python manage.py makemigrations它在我的命令行中显示以下提示...

You are trying to add a non-nullable field 'created_at' to comment without a default; we can't do that (the database needs something to populate existing rows).
Please select a fix:
1) Provide a one-off default now (will be set on all existing rows)
2) Quit, and let me add a default in models.py
Select an option: 1
Please enter the default value now, as valid Python
The datetime and django.utils.timezone modules are available, so you can do e.g. timezone.now()

3）此时我输入timezone.now()在所有模型上，完成后它成功地为我创建了迁移文件。

4）我跑python manage.py migrate并得到TypeError上面显示的消息。

我尝试过的事情...

1）通过Stack Overflow查找类似问题（无济于事）...
2）删除migrations文件并尝试使用datetime.datetime.now()
3）删除迁移文件并尝试使用简单整数1.

所有这些尝试都没有结果。

完整的命令行回溯...

(env)alopex@Alopex:~/repos/hacker_news$ python manage.py migrate
Operations to perform:
  Apply all migrations: admin, auth, sessions, hackernews, contenttypes
Running migrations:
  Rendering model states... DONE
  Applying hackernews.0003_auto_20151226_1701...Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/home/alopex/repos/hacker_news/env/lib/python3.4/site-packages/django/core/management/__init__.py", line 350, in execute_from_command_line
    utility.execute()
  File "/home/alopex/repos/hacker_news/env/lib/python3.4/site-packages/django/core/management/__init__.py", line 342, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/alopex/repos/hacker_news/env/lib/python3.4/site-packages/django/core/management/base.py", line 348, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/home/alopex/repos/hacker_news/env/lib/python3.4/site-packages/django/core/management/base.py", line 399, in execute
    output = self.handle(*args, **options)
  File "/home/alopex/repos/hacker_news/env/lib/python3.4/site-packages/django/core/management/commands/migrate.py", line 200, in handle
    executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial)
  File "/home/alopex/repos/hacker_news/env/lib/python3.4/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/alopex/repos/hacker_news/env/lib/python3.4/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/alopex/repos/hacker_news/env/lib/python3.4/site-packages/django/db/migrations/executor.py", line 198, in apply_migration
    state = migration.apply(state, schema_editor)
  File "/home/alopex/repos/hacker_news/env/lib/python3.4/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/alopex/repos/hacker_news/env/lib/python3.4/site-packages/django/db/migrations/operations/fields.py", line 62, in database_forwards
    field,
  File "/home/alopex/repos/hacker_news/env/lib/python3.4/site-packages/django/db/backends/base/schema.py", line 382, in add_field
    definition, params = self.column_sql(model, field, include_default=True)
  File "/home/alopex/repos/hacker_news/env/lib/python3.4/site-packages/django/db/backends/base/schema.py", line 145, in column_sql
    default_value = self.effective_default(field)
  File "/home/alopex/repos/hacker_news/env/lib/python3.4/site-packages/django/db/backends/base/schema.py", line 210, in effective_default
    default = field.get_db_prep_save(default, self.connection)
  File "/home/alopex/repos/hacker_news/env/lib/python3.4/site-packages/django/db/models/fields/related.py", line 910, in get_db_prep_save
    return self.target_field.get_db_prep_save(value, connection=connection)
  File "/home/alopex/repos/hacker_news/env/lib/python3.4/site-packages/django/db/models/fields/__init__.py", line 728, in get_db_prep_save
    prepared=False)
  File "/home/alopex/repos/hacker_news/env/lib/python3.4/site-packages/django/db/models/fields/__init__.py", line 968, in get_db_prep_value
    value = self.get_prep_value(value)
  File "/home/alopex/repos/hacker_news/env/lib/python3.4/site-packages/django/db/models/fields/__init__.py", line 976, in get_prep_value
    return int(value)
TypeError: int() argument must be a string, a bytes-like object or a number, not 'datetime.datetime'

完整迁移文件...

# -*- coding: utf-8 -*-
# Generated by Django 1.9 on 2015-12-26 17:01
from __future__ import unicode_literals

import datetime
from django.conf import settings
from django.db import migrations, models
import django.db.models.deletion
from django.utils.timezone import utc


class Migration(migrations.Migration):

dependencies = [
    migrations.swappable_dependency(settings.AUTH_USER_MODEL),
    ('hackernews', '0002_auto_20151224_1605'),
]

operations = [
    migrations.AddField(
        model_name='comment',
        name='created_at',
        field=models.DateTimeField(auto_now_add=True, default=datetime.datetime(2015, 12, 26, 17, 1, 23, 211181, tzinfo=utc)),
        preserve_default=False,
    ),
    migrations.AddField(
        model_name='comment',
        name='user',
        field=models.ForeignKey(default=datetime.datetime(2015, 12, 26, 17, 1, 28, 128127, tzinfo=utc), on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL),
        preserve_default=False,
    ),
    migrations.AddField(
        model_name='commentvote',
        name='created_at',
        field=models.DateTimeField(auto_now_add=True, default=datetime.datetime(2015, 12, 26, 17, 1, 34, 85491, tzinfo=utc)),
        preserve_default=False,
    ),
    migrations.AddField(
        model_name='post',
        name='created_at',
        field=models.DateTimeField(auto_now_add=True, default=datetime.datetime(2015, 12, 26, 17, 1, 37, 779457, tzinfo=utc)),
        preserve_default=False,
    ),
    migrations.AddField(
        model_name='postvote',
        name='created_at',
        field=models.DateTimeField(auto_now_add=True, default=datetime.datetime(2015, 12, 26, 17, 1, 41, 794803, tzinfo=utc)),
        preserve_default=False,
    ),
]

问题出在新的ForeignKey:

migrations.AddField(
    model_name='comment',
    name='user',
    field=models.ForeignKey(default=datetime.datetime(2015, 12, 26, 17, 1, 28, 128127, tzinfo=utc), on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL),
    preserve_default=False,
),

显然默认值是错误的。我认为您错误地插入了它。

您应该指定用户的主键，或者给出User object.