Question

我设置了我的模型，以便在将商品添加到商店时，它会根据计数为其提供自己的店内ID。我称之为SPI。加法功能正常，它可以正确分配正确的SPI。但我在删除功能方面遇到了麻烦。当从表中删除一个对象时，我需要它来遍历剩余的对象并将它们的SPI设置为少一个。但是我一直收到错误StoreLiquor matching query does not exist. Lookup parameters were {'StoreLiquorID': 7, 'storeID': <Store: test store>}我没有正确地进行查询吗？

模特：

class Store(models.Model):
    StoreID = models.AutoField(primary_key=True)
    user = models.ManyToManyField(User)
    StoreName = models.CharField('Store Name', max_length=30)
    (other things here too but probably not necessary for this case)

class StoreLiquor(models.Model):
    StoreLiquorID = models.AutoField(primary_key=True)
    liquorID = models.ForeignKey(Liquor)
    storeID = models.ForeignKey(Store)
    StorePrice = models.DecimalField('Store Price', max_digits=5, decimal_places=2)
    SPI = models.PositiveIntegerField('SPI', max_length=10)

观点：

def delete(request, liquor_id, store_id):
    storeID = Store.objects.get(StoreID=store_id)
    StLiquor = StoreLiquor.objects.get(storeID=store_id, StoreLiquorID=liquor_id)
    LiqSPI = StLiquor.SPI
    SPIcount = StoreLiquor.objects.filter(storeID=store_id).count()

    for newSPI in range(LiqSPI, SPIcount):
        newStLiquor = StoreLiquor.objects.get(storeID=storeID, StoreLiquorID=newSPI)
        newStLiquor.SPI = newSPI-1

    StLiquor.delete()
    return HttpResponseRedirect(request.META.get('HTTP_REFERER'))

Answer 1

而不是for循环，请将queryset.update与django.db.models.F一起使用：

from django.db.models import F

...

StoreLiquor.objects.filter(storeID=storeID, SPI__gt=LiqSPI).update(SPI=F('SPI')-1)

循环对象并更改其值

1 个答案: