Django 如何在使用信号从另一个模型输入后更新某些特定字段数据

Question

我对 Django 信号有一些问题。在将数据输入 PenelitiPemindahanWP 后，我想将 PermohonanWP 状态模型字段从 'PROSES' 更新为 'SUCCESS'。（假设我已经将数据输入到状态为 'PROSES' 的 PermohonanWP 模型）

这是我的 model.py

class PermohonanWP(models.Model):
      npwp = models.CharField(max_length=15, null=False)
      nama = models.CharField(max_length=100, null=False)
      status = models.CharField(max_length=20, null=True)

class PenelitiPemindahanWP(models.Model):
      permohonan_pemindahan = models.ForeignKey(PermohonanWP, on_delete=models.CASCADE)
      nomor_lhp = models.IntegerField(null=True)
      nomor_st = models.CharField(max_length=50, null=True)

这里是我输入的信号 model.py

@receiver(post_save, sender=PenelitiPemindahanWP, dispatch_uid="update_permohonan_id")
def update_permohonan(sender, instance, **kwargs):
    pemohon = PermohonanWP.objects.get(id=instance.permohonan_pemindahan)
    pemohon.status = "SUCCESS"
    pemohon.save()

我想从 PermohonanWP 更新状态字段，但是每当我提交保存按钮时，它都没有保存，也没有更新字段。

Answer 1

更正这个

pemohon = PermohonanWP.objects.get(id=instance.permohonan_pemindahan)

至

pemohon = PermohonanWP.objects.get(id=instance.permohonan_pemindahan.id)

或

甚至简单:

pemohon = instance.permohonan_pemindahan

Answer 2

您需要在 apps config ready method

中导入您的信号

apps.py

from django.apps import AppConfig

class <App_name>Config(AppConfig):
    name = '<app name>'

    def ready(self): 
        import <app name>.signals

init.py

default_app_config = '<app_name>.apps.<App_name>Config'    # first letter capital

你的信号应该是这样的，

@receiver(post_save, sender=PenelitiPemindahanWP, dispatch_uid="update_permohonan_id")
def update_permohonan(sender, instance, **kwargs):
    pemohon = PermohonanWP.objects.get(id=instance.permohonan_pemindahan.id)
    pemohon.status = "SUCCESS"
    pemohon.save()

希望有用。

提示:

如果您在状态字段中使用选项会更好。

In my opinion, whenever it’s possible integers should be used for storing information about some resource status. There is a big advantage of such a solution. After adding a database index to that field, search performance will be more efficient when using an integer field instead of a char field. Another advantage is the fact that we can manipulate ordering in such a field. For example: In the model there is a status field with the allowed choices: New = 1, Draft = 2, Published = 3. If we want to order those Django models instances by status from the new created to published, we can now easily add order on that field (ascending on integer field). ref

一种方法；

models.py

    ...
    # status
    PENDING = 1
    PROCESSING = 2
    DELIVERED = 3
    CANCELED = 4

    ORDER_STATUS = [
        (PENDING, 'Pending'),
        (PROCESSING, 'Processing'),
        (DELIVERED, 'Delivered'),
        (CANCELED, 'Canceled')
    ]

    status = models.PositiveSmallIntegerField(choices=ORDER_STATUS, default=PENDING)
   ...

Django 如何在使用信号从另一个模型输入后更新某些特定字段数据

Django How to update some specific fields data after input from another model using signals

django

django-signals