如何在 Django 中获取当前日期和时间 [重复]

Question

我无法弄清楚我在做什么错误

我知道这个问题已经被问过了，但仍然面临这些错误

from datetime import datetime

class Images(models.Model):
  created_date = models.IntegerField(default=datetime.now().date())
  created_time = models.IntegerField(default=datetime.now().time())
  road_name = models.CharField(max_length = 100, default = 'NULL')

上面的代码出错了

Applying images.0002_auto_20200109_0728...Traceback (most recent call last):
  File "manage.py", line 15, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/__init__.py", line 375, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 323, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 364, in execute
    output = self.handle(*args, **options)
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 83, in wrapped
    res = handle_func(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/django/core/management/commands/migrate.py", line 234, in handle
    fake_initial=fake_initial,
  File "/usr/local/lib/python3.5/dist-packages/django/db/migrations/executor.py", line 117, in migrate
    state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "/usr/local/lib/python3.5/dist-packages/django/db/migrations/executor.py", line 147, in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File "/usr/local/lib/python3.5/dist-packages/django/db/migrations/executor.py", line 245, in apply_migration
    state = migration.apply(state, schema_editor)
  File "/usr/local/lib/python3.5/dist-packages/django/db/migrations/migration.py", line 124, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "/usr/local/lib/python3.5/dist-packages/django/db/migrations/operations/fields.py", line 249, in database_forwards
    schema_editor.alter_field(from_model, from_field, to_field)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/base/schema.py", line 535, in alter_field
    old_db_params, new_db_params, strict)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/postgresql/schema.py", line 122, in _alter_field
    new_db_params, strict,
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/base/schema.py", line 648, in _alter_field
    old_default = self.effective_default(old_field)
  File "/usr/local/lib/python3.5/dist-packages/django/db/backends/base/schema.py", line 233, in effective_default
    return field.get_db_prep_save(self._effective_default(field), self.connection)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/fields/__init__.py", line 789, in get_db_prep_save
    return self.get_db_prep_value(value, connection=connection, prepared=False)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/fields/__init__.py", line 1429, in get_db_prep_value
    value = self.get_prep_value(value)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/fields/__init__.py", line 1408, in get_prep_value
    value = super().get_prep_value(value)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/fields/__init__.py", line 1268, in get_prep_value
    return self.to_python(value)
  File "/usr/local/lib/python3.5/dist-packages/django/db/models/fields/__init__.py", line 1393, in to_python
    params={'value': value},
django.core.exceptions.ValidationError: ["'07:28:18' value has an invalid format. It must be in YYYY-MM-DD HH:MM[:ss[.uuuuuu]][TZ] format."]

当我使用 Django 核心 DateTimeField 时，我常常会卡在 auto_now_add 和 auto_now 字段中

class Images(models.Model):
  created_date = models.DateTimeField(auto_now_add=True, default=timezone.now())
  created_time = models.TimeField(auto_now=True, default=timezone.now())

错误

SystemCheckError: System check identified some issues:

ERRORS:
images.PotholeImages.created_date: (fields.E160) The options auto_now, auto_now_add, and default are mutually exclusive. Only one of these options may be present.
images.PotholeImages.created_time: (fields.E160) The options auto_now, auto_now_add, and default are mutually exclusive. Only one of these options may be present.

谢谢

Answer 1

我强烈建议不要使用IntegerFields，但在这里使用DateTimeField [Django-doc]。您可以将True 传递给auto_now_add=… parameter [Django-doc] 以自动设置当前时间：

class MyModel(models.Model):
    created = models.DateTimeField(auto_now_add=True)
    road_name = models.CharField(max_length=100)

这不仅会在您创建新的MyModel 记录时设置当前时间，还会使字段不可编辑（将editable=… parameter [Django-doc] 设置为False），并将blank=… parameter [Django-doc] 设置为@ 987654334@.

请不要将DateTimeField 拆分为两个单独的字段（DateField 和TimeField）。时间证明是“日期敏感的”。事实上，时区和夏令时意味着某些日期在时间上执行“转换”。