如何過濾 Django 模型以從不同的表中獲取字段值

Question

我正在開發 Django 票務應用程序，其中我有一個引腳狀態檢查視圖。 我想查詢 Pin Model 以了解該 PIN 是否已激活，如果激活則查詢訪客和 Profile Models 以獲取訪客資料信息並顯示在模板中。

我已經能夠使用 Django Forms 進行搜索以顯示 PIN 詳細信息，但如果 PIN 已激活，則無法找出獲取訪客配置文件的邏輯代碼。 有人可能希望提供幫助。 謝謝。

型號代碼：

class Profile(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE, null = True)
    surname = models.CharField(max_length=20, null=True)
    othernames = models.CharField(max_length=40, null=True)
    gender = models.CharField(max_length=6, choices=GENDER, blank=True, null=True)
    phone = PhoneNumberField()
    image = models.ImageField(default='avatar.jpg', blank=False, null=False, upload_to ='profile_images', 
)


    #Method to save Image
    def save(self, *args, **kwargs):
        super().save(*args, **kwargs)
        img = Image.open(self.image.path)
        #Check for Image Height and Width then resize it then save
        if img.height > 200 or img.width > 150:
            output_size = (150, 250)
            img.thumbnail(output_size)
            img.save(self.image.path)

       def __str__(self):
           return f'{self.user.username}-Profile'

class Pin(models.Model):
    ticket = models.ForeignKey(Ticket, on_delete=models.CASCADE)
    value = models.CharField(max_length=6, default=generate_pin, blank=True)
    added = models.DateTimeField(auto_now_add=True,  blank=False)
    reference = models.UUIDField(primary_key = True, editable = False, default=uuid.uuid4)
    status = models.CharField(max_length=30, default='Not Activated')

    #Save Reference Number
    def save(self, *args, **kwargs):
         self.reference == str(uuid.uuid4())
         super().save(*args, **kwargs) 

    def __unicode__(self):
        return self.ticket

    class Meta:
        unique_together = ["ticket", "value"]

    def __str__(self):
        return f"{self.ticket}"

    def get_absolute_url(self):
        return reverse("pin-detail", args=[str(self.id)])

class Guest(models.Model):
    guest_name = models.CharField(max_length=30, null=True)
    pin = models.CharField(max_length=6, null=True)


    def __str__(self):
        return f"{self.guest_name}" 

我的觀點：

def Pin_Searcht(request):
    context = {}
    #Search PIN Form
    searchForm = SearchEventTicketForm(request.GET or None)


    if searchForm.is_valid():
        #Value of search form
        value = searchForm.cleaned_data['value']
  

        user_pin = Pin.objects.filter(value=value)
    
      
    else:
        user_pin = Pin.objects.order_by('-added')[:2]
      
    page_title = "Search and Print PINs"
    context.update ({
    'page_title':page_title,
    'list_pins':paged_listPin,
    'searchForm':searchForm,
    'page_title':"PIN Status",

    })
    return render(request, 'user/pin_list.html', context)

Answer 1

我看不到引腳 Model 和配置文件模型之間有任何關系，我確實在客人中看到了

• Guest.pin == Pin.value

如果您希望搜索返回多個 Pin 圖 + 多個客人

# This is a Queryset (list of Pins)
#   [ <Pin #1> ]
user_pin_list = Pin.objects.filter(value=value)

# Get Guests with Pins (list)
#   [ <Guest #1> ]
guest_list Guest.objects.filter(pin__in=user_pin_list)

如果您希望搜索返回單個 Pin + 單個訪客

# Get Pin (Single)
#   <Pin #1>
user_pin_or_none = Pin.objects.filter(value=value).first()

# Get Guest with Pin (Single)
#   <Guest #1>
guest_or_none = Guest.objects.filter(pin=user_pin).first()

---

您也可以在每個 Guest + Table 模型中添加一個 ForignKey 到 Pin：

class Pin(models.Model):
    value = models.CharField(max_length=6, default=generate_pin, blank=True)


class Profile(models.Model):
    # other fields
    pin = models.ForeignKey(Pin, on_delete=models.CASCADE)

class Guest(models.Model):
    # other fields
    pin = models.ForeignKey(Pin, on_delete=models.CASCADE)

然后使用：

user_pin_or_none = Pin.objects.filter(value=value).first()

guest_or_none = Guest.objects.filter(pin=user_pin_or_none).first()
profile_or_none = Profile.objects.filter(pin=user_pin_or_none).first()

# -------------------------
# or you could do this: `__` allows you to filter fields in a ForeignKey (useful!)
guest_or_none = Guest.objects.filter(pin__value=value).first()
profile_or_none = Profile.objects.filter(pin__value=value).first()