Django-TypeError:需要字符串或bu

Question

喂，我在模型中添加了一个字段，当我试图在终端中执行migrate时，它会给出这个错误，有人知道这可能是什么吗？

一、二、二、三、三、四、四、四、四、四、四、四、四、六、六、六、六

  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
    utility.execute()
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/core/management/__init__.py", line 377, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/core/management/base.py", line 288, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/core/management/base.py", line 338, in execute
    output = self.handle(*args, **options)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/core/management/commands/migrate.py", line 161, in handle
    executor.migrate(targets, plan, fake=options.get("fake", False))
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/db/migrations/executor.py", line 68, in migrate
    self.apply_migration(migration, fake=fake)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/db/migrations/executor.py", line 102, in apply_migration
    migration.apply(project_state, schema_editor)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/db/migrations/migration.py", line 108, in apply
    operation.database_forwards(self.app_label, schema_editor, project_state, new_state)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/db/migrations/operations/fields.py", line 139, in database_forwards
    schema_editor.alter_field(from_model, from_field, to_field)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/db/backends/schema.py", line 454, in alter_field
    self._alter_field(model, old_field, new_field, old_type, new_type, old_db_params, new_db_params, strict)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/db/backends/sqlite3/schema.py", line 199, in _alter_field
    self._remake_table(model, alter_fields=[(old_field, new_field)])
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/db/backends/sqlite3/schema.py", line 137, in _remake_table
    self.create_model(temp_model)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/db/backends/schema.py", line 212, in create_model
    definition, extra_params = self.column_sql(model, field)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/db/backends/schema.py", line 124, in column_sql
    default_value = self.effective_default(field)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/db/backends/schema.py", line 187, in effective_default
    default = field.get_db_prep_save(default, self.connection)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/db/models/fields/__init__.py", line 627, in get_db_prep_save
    prepared=False)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/db/models/fields/__init__.py", line 1290, in get_db_prep_value
    value = self.get_prep_value(value)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/db/models/fields/__init__.py", line 1269, in get_prep_value
    value = super(DateTimeField, self).get_prep_value(value)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/db/models/fields/__init__.py", line 1171, in get_prep_value
    return self.to_python(value)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/db/models/fields/__init__.py", line 1228, in to_python
    parsed = parse_datetime(value)
  File "/Users/Derek/.virtualenvs/tasks/lib/python2.7/site-packages/django/utils/dateparse.py", line 70, in parse_datetime
    match = datetime_re.match(value)
TypeError: expected string or buffer

模型.py

class Lead(models.Model):
    title = models.CharField(choices=TITLE_CHOICES, max_length=20, blank=True, default='')
    first_name = models.CharField(max_length=80, blank=True, default='')
    last_name = models.CharField(max_length=80, blank=True)
    company = models.CharField(max_length=80, blank=True)
    position = models.CharField(max_length=50, blank=True, default='')
    location = models.CharField(max_length=100, blank=True)
    currently_using_sms = models.CharField(choices=CURRENTLY_USING_SMS, default='',  max_length=30)
    services_interested_in = models.ManyToManyField(Services)
    phone_number = models.CharField(blank=True, max_length=20, default='')
    mobile_number = models.CharField(blank=True, max_length=11, default='')
    email = models.EmailField(blank='True', default='')
    best_day_to_contact = models.DateTimeField(blank=False, null=True)
    notes = models.TextField(blank=True)
    assign_to = models.ForeignKey(User, db_index=True, blank=True, null=True, default=None)
    lead_source = models.ForeignKey(LeadSource, db_index=True, blank=True, null=True)
    status = models.CharField(choices=LEAD_STATUS, max_length=100, default='1')

Answer 1

Django的DateTimeField通常与Python datetime和date对象一起工作，但是has an undocumented feature of being able to automatically parse strings into ^{} objects。在您的DateTimeField声明中，您有

default=False

它既不是datetime，也不是date。因此，Django试图为您自动解析它。如果不这样做，它就会发出一个神秘的信息。

根据您的具体需要，您应该替换或删除default=False参数。

Answer 2

我相信您在以下行的default=False中有错误：

    completion_date = models.DateTimeField(blank=False, null=True, default=False)

False不是有效日期default需要。改用default=datetime.now。

Answer 3

我以前也有同样的问题。我尝试了default=False，但没有做任何更改。然后添加default=timezone。现在，它可以正常工作了。唯一的问题是日期字段不显示在管理部分。

更改此字段：

best_day_to_contact = models.DateTimeField(blank=False, null=True)

对于此字段：

from django.utils import timezone
best_day_to_contact = models.DateTimeField(default=timezone.now)

我想也许你的问题可以用这个办法解决。