Django 如何將圖像上傳到表單

Question

這是我與表單關聯的代碼：

# models

class Date(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE, null=True)
    place = models.ForeignKey('Place', on_delete=models.CASCADE, null=True)
    title = models.CharField(max_length=64, null=True)


class Photo(models.Model):
    date = models.ForeignKey('Date', on_delete=models.CASCADE)
    image = models.ImageField(verbose_name='Photos', upload_to='media/date/photos/')

# form

class DateForm(forms.ModelForm):
    image = forms.ImageField()
    class Meta:
        model = Date
        exclude = ('user',)

# view

class CreateDateView(LoginRequiredMixin, CreateView):
    template_name = 'app/date/form.html'
    form_class = DateForm

    def form_valid(self, form):
        form.instance.user = self.request.user
        form.save() # by the way why do I save this form? Is it okay to save it in form_valid method?
        photos = self.request.FILES.getlist('image')
        for photo in photos:
            Photo.objects.create(image=photo)
        return super().form_valid(form)

問題是如果需要Date模型 ID，如何保存 Photo 對象。 它引發了NOT NULL 約束失敗：app_photo.date_id據我了解，我必須編寫如下內容：

Photo.objects.create(date=date_from_the_form, image=photo)

但是如何從 Date 模型中獲取 pk 呢？ 希望您理解我的問題，如果有任何問題，請隨時在評論部分寫下。 提前致謝！

錯誤

Answer 1

您需要先創建日期對象。 另外，每個日期都是獨一無二的嗎？ 如果是這樣，您需要更改模型元聲明以包含unique_together 。

創建每個對象時，您還需要避免 for 循環。 它非常昂貴，因為每次調用 save() 都會往返於數據庫。 這就是bulk_create的用途，它將您的數據庫接觸限制為一個命令來創建多個對象。

這是讓你開始的偽代碼：

if len(photos) > 0:  # don't create a date if there aren't photos
  date = Date() # add your arguments

  filtered = Date.objects.filter(date=date)

  date = date.create() if not filtered.exists() else date = filtered[0]  # but this is potentially dangerous if you risk duplicate dates. Only use this if you know it's the correct date
  photos = [Photo(date=date,image=p) for p in photos]
  Photo.objects.bulk_create(photos)

祝你好運！

Answer 2

您需要保存照片對象：

def form_valid(self, form):
    form.instance.user = self.request.user
    form.save() # by the way why do I save this form? Is it okay to save it in form_valid method?
    photos = self.request.FILES.getlist('image')
    for photo in photos:
        temp = Photo.objects.create(image=photo)
        temp.save()
    return super().form_valid(form)