Django通过信号保存在另一个表中

Question

我有一个创建视图(Loan_assetCreateView(generic.CreateView))，如果一个资产要被借出，当它将在一个名为Loan_asset(models.Model)的模型中返回时，我将保存。然后我在另一个模型asset (model. model)中拥有这个资产。我想一旦我把我的数据保存在我的Loan_assetCreateView(generic.CreateView)中，即在资产中设置值。is_lend to True。通过信号,@receiver (postrongave我在努力保存价值。但它反而创造了另一种资产。我做错了什么，我该怎么做?

我models.py:

class Asset(models.Model):
# Relationships
room = models.ForeignKey("asset_app.Room", on_delete=models.SET_NULL, blank=True, null=True)
model_hardware = models.ForeignKey("asset_app.Model_hardware", on_delete=models.SET_NULL, blank=True, null=True)
# Fields
name = models.CharField(max_length=30)
serial = models.CharField(max_length=30, unique=True, blank=True, null=True, default=None)
mac_address = models.CharField(max_length=30, null=True, blank=True)
purchased_date = models.DateField(null=True, blank=True)
may_be_loaned = models.BooleanField(default=False, blank=True, null=True)
is_loaned = models.BooleanField(default=False, blank=True, null=True)
missing = models.BooleanField(default=False, blank=True, null=True)
notes = HTMLField(default="")
ip = models.CharField(max_length=90, null=True, blank=True)
created = models.DateTimeField(auto_now_add=True, editable=False)
last_updated = models.DateTimeField(auto_now=True, editable=False)
class Loan_asset(models.Model):
# Relationships
asset = models.ForeignKey("asset_app.Asset", on_delete=models.SET_NULL, blank=True, null=True)
loaner_type = models.ForeignKey("asset_app.Loaner_type", on_delete=models.SET_NULL, blank=True, null=True)
location = models.ForeignKey("asset_app.Locations", on_delete=models.SET_NULL, blank=True, null=True)
# Fields
loaner_name = models.CharField(max_length=60)
loaner_address = models.TextField(max_length=100, null=True, blank=True)
loaner_telephone_number = models.CharField(max_length=30)
loaner_email = models.EmailField()
loaner_quicklink = models.URLField(null=True, blank=True)
loan_date = models.DateField()
return_date = models.DateField()
notes = HTMLField(default="")
returned = models.BooleanField(default=False, blank=True, null=True)
created = models.DateTimeField(auto_now_add=True, editable=False)
last_updated = models.DateTimeField(auto_now=True, editable=False)
class Meta:
pass
def __str__(self):
return str(self.loaner_name)
def get_absolute_url(self):
return reverse("asset_app_loan_asset_detail", args=(self.pk,))
def get_update_url(self):
return reverse("asset_app_loan_asset_update", args=(self.pk,))

我的urls . py

`path("asset_app/loan_asset/create/", views.Loan_assetCreateView.as_view(), name="asset_app_loan_asset_create")`,

我views.py

class Loan_assetCreateView(generic.CreateView):
model = models.Loan_asset
form_class = forms.Loan_assetForm
def get_queryset(self):
queryset = super().get_queryset().order_by('asset__model_hardware__asset_type', 'asset.name')
return queryset
@receiver(post_save, sender=models.Loan_asset)
def create_transaction(sender, instance, created, **kwargs):
if created:
models.Asset.objects.create(is_loaned=True)

Answer 1

如果我理解正确，您希望Loan_asset实例的关联Asset实例将其is_loaned切换为True。如果是这种情况，那么你的信号应该是:

@receiver(post_save, sender=models.Loan_asset)
def create_transaction(sender, instance, created, **kwargs):
if created:
asset = instance.asset
asset.is_loaned = True
# asset.save()  # save entire instance, overwriting `last_updated` OR
asset.save(update_fields=["is_loaned"])  # updates only `is_loaned`