Django多对多字段更新异常：calculating相关字段无法正确更新

问题描述 #

在更新以下字段时出现异常：

• calculating_special_order_items
• calculating_floor_special_order_items
• order_total、ship_total、confirm_total、real_total、calculating_total

具体表现：

• 视图创建新Order实例并关联ship_special_order_items时，所有字段更新正常，calculating_special_order_items正确同步并在Django Admin中显示正常；
• 当通过更新confirm_special_order_items来同步更新calculating_special_order_items时，无法触发正确更新，目标字段未按预期同步数据。

相关模型代码 #

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()

已尝试的解决方案 #

• 调整模型内部逻辑（如save方法、update_total方法的执行顺序）；
• 使用Django post-save信号触发更新；
• 自定义Django Admin表单强制触发更新逻辑。

以上方法均未解决问题，耗时两天仍无进展，寻求可行的解决方案。

内容的提问来源于stack exchange，提问作者sine