解决 ValidationError: [u"'' 值的日期格式无效。它必须是 YYYY-MM-DD 格式。"] 在 Django 1.9.2 中？

Question

之前我创建了两个字段并迁移了所有内容。之后，我尝试将三个字段 title,about,birthdate 添加到模型中。 我创建了一个这样的模型：

from __future__ import unicode_literals
from django.utils import timezone
from django.db import models

# Create your models here.

class APP1Model(models.Model):
    name = models.CharField(max_length=120)
    percentage = models.CharField(max_length=120)
    title = models.CharField(max_length=100,default='Title')
    birth_date = models.DateTimeField(blank=True, null=True)
    about = models.TextField(max_length=100,null=True,default='About Yourself')

    def __unicode__(self):
        return self.name

但是当我尝试在 python shell 中迁移时，它显示如下验证错误：

Operations to perform:
  Apply all migrations: admin, contenttypes, auth, app1, sessions
Running migrations:
  Applying app1.0005_auto_20160217_1346...Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 353, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 345, 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 348, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 399, in execute
    output = self.handle(*args, **options)
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/commands/migrate.py", line 200, in handle
    executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial)
  File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 92, in migrate
    self._migrate_all_forwards(plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "/usr/local/lib/python2.7/dist-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 "/usr/local/lib/python2.7/dist-packages/django/db/migrations/executor.py", line 198, in apply_migration
    state = migration.apply(state, schema_editor)
  File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/migration.py", line 123, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "/usr/local/lib/python2.7/dist-packages/django/db/migrations/operations/fields.py", line 62, in database_forwards
    field,
  File "/usr/local/lib/python2.7/dist-packages/django/db/backends/sqlite3/schema.py", line 221, in add_field
    self._remake_table(model, create_fields=[field])
  File "/usr/local/lib/python2.7/dist-packages/django/db/backends/sqlite3/schema.py", line 103, in _remake_table
    self.effective_default(field)
  File "/usr/local/lib/python2.7/dist-packages/django/db/backends/base/schema.py", line 210, in effective_default
    default = field.get_db_prep_save(default, self.connection)
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/fields/__init__.py", line 728, in get_db_prep_save
    prepared=False)
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/fields/__init__.py", line 1301, in get_db_prep_value
    value = self.get_prep_value(value)
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/fields/__init__.py", line 1296, in get_prep_value
    return self.to_python(value)
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/fields/__init__.py", line 1273, in to_python
    params={'value': value},
django.core.exceptions.ValidationError: [u"'' value has an invalid date format. It must be in YYYY-MM-DD format."]

如何解决这个问题？我尝试了我在这里阅读的所有解决方案，但它不起作用？

我正在使用 Django：1.9.2

我的迁移文件

from __future__ import unicode_literals

from django.db import migrations, models

类迁移（migrations.Migration）：

dependencies = [
    ('app1', '0004_auto_20160217_0427'),
]

operations = [
    migrations.AddField(
        model_name='app1model',
        name='about',
        field=models.TextField(default='About Yourself', max_length=100, null=True),
    ),
    migrations.AddField(
        model_name='app1model',
        name='birth_date',
        field=models.DateField(blank=True, default='', null=True),
    ),
    migrations.AddField(
        model_name='app1model',
        name='title',
        field=models.CharField(default='', max_length=100),
    ),
]

Answer 1

几个月前我遇到了同样的问题。我刚刚删除了迁移文件夹中所有迁移文件中的生日字段更改。然后我用这个代码替换了生日：-

birthdate = models.DateTimeField(blank=True, null=True)                            

然后在应用迁移后，它工作正常......

Answer 2

看来你已经过了 DateTimeField

birth_date = models.DateTimeField(blank=True, null=True)

在您的 APP1Model(model) 和迁移中显示 DateFields

models.DateField(blank=True, default='', null=True)

首先纠正你的模型，不要通过default='' in DateField,

使用DateField 代替DatiTimeField 作为生日日期

然后删除您的迁移文件 app1.0005_auto_20160217_1346

然后运行 ​​ma​​kemigrations 和 migrate 您的应用，它会正常工作。

Answer 3

将DateField 更改为DateTimeField 不是一个坏主意。虽然，有一个DateField 和一个DateTimeField，由于某些原因它们是不同的。

当默认值以错误的格式应用于models.py 中的DateField 时，会发生此错误。

根据您的终端输出，错误发生在迁移文件0005_auto_20160217_1346.py 中。您必须在“app1/0005_auto_20160217_1346.py”中找到该迁移文件，对其进行编辑并查找：

...

migrations.AddField(
    model_name='app1model',
    name='birth_date',
    field=models.DateField(blank=True, default='<jamming-date>', null=True),
),

...

现在，您可以看到带有default 属性的DateField，其中包含格式为%d-%m-%Y 的<jamming-date>，例如。 Django 需要%Y-%m-%d 格式。

为了解决这个问题，删除default属性，保存文件并再次进行迁移。

Answer 4

只需删除迁移文件中的 default=' ' 并运行 migrate 。

之前：

migrations.AddField(
    model_name='formd',
    name='cash_payment_date',
    field=models.DateField(blank=True, default='', help_text='Date of Cash Payment', null=True),
),

之后：

migrations.AddField(
    model_name='formd',
    name='cash_payment_date',
    field=models.DateField(blank=True, help_text='Date of Cash Payment', null=True),
),

删除默认=''

跑去迁移

Answer 5

尝试将 DateTime 上的默认属性从空白“”（在我的初始迁移文件中设置）更改为 django.utils.timezone.now（在以后的迁移中）后，我遇到了同样的错误。您需要返回并编辑您的 0001_Initial.py 文件并将默认值更改为您现在想要的任何值。似乎在应用迁移时，Django 正在引用该初始文件进行验证并抛出错误，这可能有点误导，我花了几个小时试图找出原因......希望我能节省一些时间:)