python - django 中未定义 DateTimeField 错误

Question

我想删除年龄超过一天的模特的视频。

模型.py

from __future__ import unicode_literals
import urllib
from django.core.files import File 
from django.db import models
from PIL import Image
from datetime import datetime
from django.utils import timezone
import os
class video(models.Model):
    video_title = models.CharField(max_length=250)
    video_link = models.CharField(max_length=250)
    video_thumbnail = models.ImageField(upload_to = '',blank = True)
    image_url = models.CharField(max_length=250,blank = True)
    upload_date = models.DateTimeField(blank=True)
    def cache(self):
        if self.image_url and not self.video_thumbnail:
            result = urllib.urlretrieve(self.image_url)
            self.video_thumbnail.save(
                    os.path.basename(self.image_url),
                    File(open(result[0]))
                    )
            self.save()

    def __str__(self):
        return self.video_title + "," + self.video_link + "," + str(self.upload_date)

在 shell 中，我执行查询来删除时间超过一天的视频，如下所示:

video.objects.filter((datetime.datetime.now() - (upload_date)).total_hours > 24)

但我收到以下错误:

In [6]: video.objects.filter((datetime.datetime.now() - (upload_date)).total_hours > 24)
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-6-0c1ffc162513> in <module>()
----> 1 video.objects.filter((datetime.datetime.now() - (upload_date)).total_hours > 24)

NameError: name 'upload_date' is not defined

为什么我收到错误？

Answer 1

该查询是倒退的。您不能将 datetime.datetime.now() 作为第一个参数传递；这是为了比较字段名称。您需要反转查询，以便查询 upload_date 在现在负 24 小时之前的所有视频:

target_time = datetime.datetime.now() - datetime.timedelta(hours=24)
video.objects.filter(upload_date__lte=target_time)