用图像字段在Django中更新

Question

我正在尝试使用Django orm仅更新图像字段，即用户以后将添加图像并将在主表中更新

我试过了

MerchantProfile.objects.filter(id='%s'%(cd['id'])).update(photo='%s'%(cd['photo']))

但它只会更新标题，而图像不会保存在文件夹中

然后我尝试跟随

p1=MerchantProfile()
p1.id=cd['id']
if cd['photo']:
       p1.photo=cd['photo']
else:
       p1.photo=cd['uploaded_photo']
p1.save()

这将节省的形象，而且会显示错误，如payment_card不能为null

我的模特如下

class Merchantprofile:
   user = models.OneToOneField(UserProfile, related_name="merchant_profile")
   payment_card = models.OneToOneField(PaymentCard, related_name="merchant_profile")
   current_state = models.IntegerField('State', choices=STATE_CHOICES)
   name = models.CharField('Merchant Name', max_length=64)
   photo=models.ImageField(upload_to='logo',blank=True)

形成

class LogoForm(forms.Form):
     id = forms.CharField(widget=forms.HiddenInput,required=False)
     photo = forms.ImageField(
        required=False,
        label='Upload photo',
        initial=True,
        help_text='max. 4 megabytes'
    )

那么，仅通过在相关文件夹上上传照片来更新照片字段的最佳方法是什么，因为我无法每次都更新所有字段

Answer 1

尝试这个：

p1 = MerchantProfile.objects.filter(id=cd['id'])
if cd['photo']:
   p1.photo=cd['photo']
else:
   p1.photo=cd['uploaded_photo']
p1.save()