I have trouble with updating calculating_special_order_items, calculating_floor_special_order_items, order_total, ship_total, confirm_total, real_total and calculating_total. When I save a new instance with ship_special_order_items through a view it saves normally, calculating_special_order_items is updated and all totals are updated correctly and it is showed in django admin site correctly, but when I try to update calculating_special_order_items with saving confirm_special_order_items it is not updating correctly.
class Order(models.Model):
STATUS_CHOICES = [("naruceno","naruceno"), ("poslato","poslato"), ("stiglo","stiglo")]
ordering_facility = models.ForeignKey(Facility, on_delete=models.PROTECT, related_name='order_create_facility')
dispatching_facility = models.ForeignKey(Facility, on_delete=models.PROTECT, related_name='order_dispatch_facility')
order_timestamp = models.DateTimeField(auto_now_add=True)
ship_timestamp = models.DateTimeField(blank=True, null=True)
confirm_timestamp = models.DateTimeField(blank=True, null=True)
real_timestamp = models.DateTimeField(blank=True, null=True)
order_user = models.CharField(max_length=100, blank=True)
ship_user = models.CharField(max_length=100, blank=True)
confirm_user = models.CharField(max_length=100, blank=True)
real_user = models.CharField(max_length=100, blank=True)
status = models.CharField(max_length=20, choices=STATUS_CHOICES, default=STATUS_CHOICES[0][0])
product_variations = models.ManyToManyField(ProductVariation, through='OrderItem')
order_total = models.DecimalField(max_digits=10, decimal_places=0, blank=True, null=True)
ship_total = models.DecimalField(max_digits=10, decimal_places=0, blank=True, null=True)
confirm_total = models.DecimalField(max_digits=10, decimal_places=0, blank=True, null=True)
real_total = models.DecimalField(max_digits=10, decimal_places=0, blank=True, null=True)
calculating_total = models.DecimalField(max_digits=10, decimal_places=0, blank=True, null=True)
ship_special_order_items = models.ManyToManyField(SpecialOrderItem, blank=True, related_name='ship_special_order_items')
ship_floor_special_order_items = models.ManyToManyField(FloorSpecialOrderItem, blank=True, related_name='ship_floor_special_order_items')
confirm_special_order_items = models.ManyToManyField(SpecialOrderItem, blank=True, related_name='confirm_special_order_items')
confirm_floor_special_order_items = models.ManyToManyField(FloorSpecialOrderItem, blank=True, related_name='confirm_floor_special_order_items')
real_special_order_items = models.ManyToManyField(SpecialOrderItem, blank=True, related_name='real_special_order_items')
real_floor_special_order_items = models.ManyToManyField(FloorSpecialOrderItem, blank=True, related_name='real_floor_special_order_items')
calculating_special_order_items = models.ManyToManyField(SpecialOrderItem, blank=True, related_name='calculating_special_order_items')
calculating_floor_special_order_items = models.ManyToManyField(FloorSpecialOrderItem, blank=True, related_name='calculating_floor_special_order_items')
billed = models.BooleanField(default=False)
def calculate_calculating_special_order_items(self):
if self.real_special_order_items.exists():
return self.real_special_order_items.all()
elif self.confirm_special_order_items.exists():
return self.confirm_special_order_items.all()
elif self.ship_special_order_items.exists():
return self.ship_special_order_items.all()
else:
return []
def calculate_calculating_floor_special_order_items(self):
if self.real_floor_special_order_items.exists():
return self.real_floor_special_order_items.all()
elif self.confirm_floor_special_order_items.exists():
return self.confirm_floor_special_order_items.all()
elif self.ship_floor_special_order_items.exists():
return self.ship_floor_special_order_items.all()
else:
return []
def update_total(self):
self.calculating_special_order_items.set(self.calculate_calculating_special_order_items())
self.calculating_floor_special_order_items.set(self.calculate_calculating_floor_special_order_items())
ship_special_order_items_total = self.ship_special_order_items.aggregate(models.Sum('total'))['total__sum'] if self.ship_special_order_items.exists() else 0
ship_floor_special_order_items_total = self.ship_floor_special_order_items.aggregate(models.Sum('total'))['total__sum'] if self.ship_floor_special_order_items.exists() else 0
ship_specials_total = ship_special_order_items_total + ship_floor_special_order_items_total
confirm_special_order_items_total = self.confirm_special_order_items.aggregate(models.Sum('total'))['total__sum'] if self.confirm_special_order_items.exists() else 0
confirm_floor_special_order_items_total = self.confirm_floor_special_order_items.aggregate(models.Sum('total'))['total__sum'] if self.confirm_floor_special_order_items.exists() else 0
confirm_specials_total = confirm_special_order_items_total + confirm_floor_special_order_items_total
real_special_order_items_total = self.real_special_order_items.aggregate(models.Sum('total'))['total__sum'] if self.real_special_order_items.exists() else 0
real_floor_special_order_items_total = self.real_floor_special_order_items.aggregate(models.Sum('total'))['total__sum'] if self.real_floor_special_order_items.exists() else 0
real_specials_total = real_special_order_items_total + real_floor_special_order_items_total
calculating_special_order_items_total = self.calculating_special_order_items.aggregate(models.Sum('total'))['total__sum'] if self.calculating_special_order_items.exists() else 0
calculating_floor_special_order_items_total = self.calculating_floor_special_order_items.aggregate(models.Sum('total'))['total__sum'] if self.calculating_floor_special_order_items.exists() else 0
calculating_specials_total = calculating_special_order_items_total + calculating_floor_special_order_items_total
self.order_total = self.orderitem_set.aggregate(models.Sum('order_subtotal'))['order_subtotal__sum']
self.ship_total = self.orderitem_set.aggregate(models.Sum('ship_subtotal'))['ship_subtotal__sum'] + ship_specials_total if ship_specials_total > 0 and self.orderitem_set.aggregate(models.Sum('ship_subtotal'))['ship_subtotal__sum'] is not None else ship_specials_total if ship_specials_total>0 and self.orderitem_set.aggregate(models.Sum('ship_subtotal'))['ship_subtotal__sum'] is None else self.orderitem_set.aggregate(models.Sum('ship_subtotal'))['ship_subtotal__sum']
self.confirm_total = self.orderitem_set.aggregate(models.Sum('confirm_subtotal'))['confirm_subtotal__sum'] + confirm_specials_total if confirm_specials_total > 0 and self.orderitem_set.aggregate(models.Sum('confirm_subtotal'))['confirm_subtotal__sum'] is not None else confirm_specials_total if confirm_specials_total > 0 and self.orderitem_set.aggregate(models.Sum('confirm_subtotal'))['confirm_subtotal__sum'] is None else self.orderitem_set.aggregate(models.Sum('confirm_subtotal'))['confirm_subtotal__sum']
self.real_total = self.orderitem_set.aggregate(models.Sum('real_subtotal'))['real_subtotal__sum'] + real_specials_total if real_specials_total > 0 and self.orderitem_set.aggregate(models.Sum('real_subtotal'))['real_subtotal__sum'] is not None else real_specials_total if real_specials_total > 0 and self.orderitem_set.aggregate(models.Sum('real_subtotal'))['real_subtotal__sum'] is None else self.orderitem_set.aggregate(models.Sum('real_subtotal'))['real_subtotal__sum']
self.calculating_total = self.orderitem_set.aggregate(models.Sum('calculating_subtotal'))['calculating_subtotal__sum'] + calculating_specials_total if calculating_specials_total > 0 and self.orderitem_set.aggregate(models.Sum('calculating_subtotal'))['calculating_subtotal__sum'] is not None else calculating_specials_total if calculating_specials_total>0 and self.orderitem_set.aggregate(models.Sum('calculating_subtotal'))['calculating_subtotal__sum'] is None else self.orderitem_set.aggregate(models.Sum('calculating_subtotal'))['calculating_subtotal__sum']
def save(self, *args, **kwargs):
super().save(*args, **kwargs)
self.update_total()
super().save(*args, **kwargs)
def __str__(self):
return f"{self.ordering_facility} {str(self.ship_timestamp)[0:19]} {self.calculating_total}"
class OrderItem(models.Model):
order = models.ForeignKey(Order, on_delete=models.CASCADE)
product_variation = models.ForeignKey(ProductVariation, on_delete=models.PROTECT)
order_quantity = models.PositiveIntegerField(blank=True, null=True)
ship_quantity = models.PositiveIntegerField(blank=True, null=True)
confirm_quantity = models.PositiveIntegerField(blank=True, null=True)
real_quantity = models.PositiveIntegerField(blank=True, null=True)
calculating_quantity = models.PositiveIntegerField(blank=True, null=True)
order_subtotal = models.DecimalField(max_digits=10, decimal_places=0, blank=True, null=True)
ship_subtotal = models.DecimalField(max_digits=10, decimal_places=0, blank=True, null=True)
confirm_subtotal = models.DecimalField(max_digits=10, decimal_places=0, blank=True, null=True)
real_subtotal = models.DecimalField(max_digits=10, decimal_places=0, blank=True, null=True)
calculating_subtotal = models.DecimalField(max_digits=10, decimal_places=0, blank=True, null=True)
@property
def calculate_calculating_quantity(self):
if self.real_quantity is not None:
return self.real_quantity
elif self.confirm_quantity is not None:
return self.confirm_quantity
elif self.ship_quantity is not None:
return self.ship_quantity
elif self.order_quantity is not None:
return self.order_quantity
else:
return 0
@property
def calculate_order_subtotal(self):
return self.product_variation.price * self.order_quantity if self.order_quantity is not None else None
@property
def calculate_ship_subtotal(self):
return self.product_variation.price * self.ship_quantity if self.ship_quantity is not None else None
@property
def calculate_confirm_subtotal(self):
return self.product_variation.price * self.confirm_quantity if self.confirm_quantity is not None else None
@property
def calculate_real_subtotal(self):
return self.product_variation.price * self.real_quantity if self.real_quantity is not None else None
@property
def calculate_calculating_subtotal(self):
return self.product_variation.price * self.calculating_quantity if self.calculating_quantity is not None else None
def save(self, *args, **kwargs):
self.order_subtotal = self.calculate_order_subtotal
self.ship_subtotal = self.calculate_ship_subtotal
self.confirm_subtotal = self.calculate_confirm_subtotal
self.real_subtotal = self.calculate_real_subtotal
self.calculating_quantity = self.calculate_calculating_quantity
self.calculating_subtotal = self.calculate_calculating_subtotal
super().save(*args, **kwargs)
self.order.update_total()
I have tried everything for 2 days with code inside model, even with post-save signal, even with custom modelform for django admin, I am out of solutions, please help me if you encountered same problem and if you resolved it successfully. Thank You.
with code inside model, even with post-save signal, even with custom modelform for django admin.
I believe that. All these methods will not work, because Django populates or updates the ManyToManyField [Django-doc] after it has saved the object, so by the time your def save(..) runs, or your post_save signal [Django-doc], since at that time, there is no data yet, or the data is outdated.
You could work with a m2m_changed signal [Django-doc] and subscribe this on all ManyToManyFields, but I am not a fan of this either: if the data of a ProductVariation itself for example changes, than this could also have impact, without the Order, or the .product_variations changing.
I think it makes more sense to work with a @property [python-doc], or .annotate(…) [Django-doc] when you need to do this in bulk or to filter on the aggregate.
Keeping an "aggregate" in a model object is often not a good idea. The main problem is that a lot of scenarios can trigger the aggregate to get outdated, and catching all these cases is almost impossible. I summarized some problems with signals in this article [django-antipatterns].