英文:
How to set the current time to "TimeField()" as a default value in Django Models?
问题
文档中在DateField.auto_now_add下面说：
> 当对象首次创建时，自动将字段设置为当前时间。...如果您想要能够修改此字段，请设置以下内容，而不是auto_now_add=True：
- 对于
DateField：default=date.today-from datetime.date.today() - 对于
DateTimeField：default=timezone.now-from django.utils.timezone.now()
因此，对于DateField()和DateTimeField()，我可以分别将当前日期和时间设置为默认值，如下所示：
from datetime import date
from django.utils import timezone
class MyModel(models.Model):
date = models.DateField(default=date.today) # 这里
datetime = models.DateTimeField(default=timezone.now) # 这里
现在，如何将当前时间设置为TimeField()的默认值，如下所示：
class MyModel(models.Model): # ?
time = models.TimeField(default=...)
英文:
The doc says below in DateField.auto_now_add:
> Automatically set the field to now when the object is first created. ... If you want to be able to modify this field, set the following instead of auto_now_add=True:
- For
DateField:default=date.today-from datetime.date.today() - For
DateTimeField:default=timezone.now-from django.utils.timezone.now()
So to DateField() and DateTimeField(), I can set the current date and time respectively as a default value as shown below:
from datetime import date
from django.utils import timezone
class MyModel(models.Model):
date = models.DateField(default=date.today) # Here
datetime = models.DateTimeField(default=timezone.now) # Here
Now, how can I set the current time to TimeField() as a default value as shown below?
class MyModel(models.Model): # ?
time = models.TimeField(default=...)
答案1
得分: 1
你可以使用一个可调用对象：
from django.utils import timezone
def <b>current_time</b>():
return timezone.now()<b>.time()</b>;
class MyModel(models.Model):
time = models.TimeField(default=<b>current_time</b>)
每次你定义一个新的 MyModel，如果没有传递时间参数，它将调用 current_time 方法，因此返回当前（带时区的）时间的时间部分。
重要的是不要使用括号，所以 default=current_time，而不是 <s>default=current_time()`。
英文:
You can use a callable:
<pre><code>from django.utils import timezone
def <b>current_time</b>():
return timezone.now()<b>.time()</b>
class MyModel(models.Model):
time = models.TimeField(default=<b>current_time</b>)</code></pre>
each time you define a new MyModel and the time is not passed, it will call the current_time method and thus return the time component of the current (timezoned time).
It is important not to use parenthesis, so default=current_time, not <s>default=current_time()</s>.
答案2
得分: 0
你可以将current_time设置为没有()的形式，将timezone.now().time()作为TimeField()的默认值，如下所示。*不要使用()设置current_time()，因为默认时间是在Django服务器启动时确定的（不变）：
from django.utils import timezone
def current_time(): # 这里
return timezone.now().time()
class MyModel(models.Model): # 不要设置“current_time()”
time = models.TimeField(default=current_time)
请注意，不要使用()将timezone.now().time()设置为TimeField()的默认值，如下所示，因为默认时间是在Django服务器启动时确定的（不变）：
from django.utils import timezone
class MyModel(models.Model): # 不要设置“timezone.now().time()”
time = models.TimeField(default=timezone.now().time())
此外，不要将timezone.now().time设置为没有()的形式，作为TimeField()的默认值，如下所示，因为在运行python manage.py makemigrations时会出错：
from django.utils import timezone
class MyModel(models.Model): # 不要设置“timezone.now().time”
time = models.TimeField(default=timezone.now().time)
另外，我不建议使用DateField()和TimeField()，因为它们不与settings.py中的TIME_ZONE一起工作，正如我在提问时所询问的，而DateTimeField()可以。
英文:
You can set current_time without () which returns timezone.now().time() to TimeField() as a default value as shown below. *Don't set current_time() with () because the default time becomes when the Django server starts (Unchanged):
from django.utils import timezone
def current_time(): # Here
return timezone.now().time()
class MyModel(models.Model): # Don't set "current_time()"
time = models.TimeField(default=current_time)
Be careful, don't set timezone.now().time() with () to TimeField() as a default value as shown below because the default time becomes when the Django server starts (Unchanged):
from django.utils import timezone
class MyModel(models.Model): # Don't set "timezone.now().time()"
time = models.TimeField(default=timezone.now().time())
And, don't set timezone.now().time without () to TimeField() as a default value as shown below because there is an error when running python manage.py makemigrations:
from django.utils import timezone
class MyModel(models.Model): # Don't set "timezone.now().time"
time = models.TimeField(default=timezone.now().time)
In addition, I don't recommend to use DateField() and TimeField() because they don't work with TIME_ZONE in settings.py as I asked the question while DateTimeField() does.
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