Question

我有两个模型，如下所示。

PRODUCT_TYPE=(('TL','Tubeless Tyre'), ('TT','Tubed Tyre'), ('NA','Not applicable'))
class Product(models.Model):
    product_group=models.ForeignKey('productgroup.ProductGroup', null=False,blank=False)
    manufacturer=models.ForeignKey(Manufacturer, null=False,blank=False)
    product_type=models.CharField(max_length=2, choices=PRODUCT_TYPE,)

    opening_stock=models.PositiveIntegerField(default=0)

    def __str__(self):
        return '%s (%s, %s, %s) o.stock = %d ' % (self.product_group, self.manufacturer, self.product_type ,self.opening_stock)

        unique_together = ('product_group', 'manufacturer','product_type')
    def get_total_stock_in(self):
        return Stock.objects.filter(product=self.id,ttype='I').aggregate(Sum('quantity'))
    def get_total_stock_out(self):
        return Stock.objects.filter(product=self.id,ttype='O').aggregate(Sum('quantity'))

和

TRANSACTION_TYPE=(('I','Stock In'),('O','Stock Out'))
class Stock(models.Model):
    product=models.ForeignKey('product.Product', blank=False,null=False)
    date=models.DateField(blank=False, null=False,)
    quantity=models.PositiveIntegerField(blank=False, null=False)
    ttype=models.CharField(max_length=1,verbose_name="Ttransaction type",choices=TRANSACTION_TYPE, blank=False)
    added_date=models.DateTimeField(blank=False, auto_now=True)
    def get_absolute_url(self):
        return reverse('product_detail', args=[str(self.product.id)])
    def __str__(self):
        return ('[%s] %s (%s) %d' %(self.product, self.date, self.ttype, self.quantity))

和视图为..

class ProductDetail(DetailView):
    model=Product
    def get_context_data(self, **kwargs):
        context = super(ProductDetail, self).get_context_data(**kwargs)
        product_id=self.kwargs['pk']
                    context['total_stock_in']=Stock.objects.filter(product=product_id,ttype='I').aggregate(Sum('quantity'))
        context['total_stock_out']=Stock.objects.filter(product=product_id,ttype='O').aggregate(Sum('quantity'))

        return context

这是我的模板。

Opening stock : {{object.opening_stock}}
<br>
Total Stock In: {{total_stock_in.quantity__sum}}
<br>
Total Stock Out: {{total_stock_out.quantity__sum}}
<br>
Balance stock : ???

现在，在模板product_detail.html内，我需要将opens_stock + total_stock_in-total_stock_out的结果显示为当前余额。

感谢您的任何意见。

Answer 1

我最终如下所示。

为模型添加了一种方法

class Product(models.Model):
...........
def get_balance_stock(self):
        return (self.opening_stock+self.get_total_stock_in()['quantity__sum']
                - self.get_total_stock_out()['quantity__sum'])

然后从模板中调用它

Balance stock: {{object.get_balance_stock}}

django - 对模板

1 个答案: