Question

我有两张桌子Topmost和Pincode：

class Pincode(models.Model):
    pincode = models.CharField("PinCode", max_length=6, null=False)
    geom = GeopositionField("Location")

class Topmost(models.Model):
     pincode = models.ForeignKey(Pincode, unique=True)
     rating_pincode = models.CharField("Total Rating points", max_length=255, null=True, blank=True)
     frequency = models.CharField("Number of user", max_length=255, null=True, blank=True)
     normalized_rank = models.FloatField(null=True, blank=True)

现在我想在创建新的pincodes时创建一个自动进入最顶层的条目。所以在views.py中：

id_past_entries = Topmost.objects.all().values_list('pincode_id', flat=True)
    new_entries = Pincode.objects.exclude(id__in=id_past_entries).values_list('id', flat=True)

    for new_id in new_entries:
        new = Pincode.objects.get(id = new_id)
        Topmost.objects.create(pincode=new,rating_pincode=0, frequency=0, normalized_rank=0 )
        Topmost().save()

但是它给出了错误

IntegrityError：NOT NULL约束失败：display_topmost.pincode_id

任何想法??

Answer 1

为什么使用Topmost().save()？

Topmost.objects.create(pincode=new,rating_pincode=0, frequency=0, normalized_rank=0 )已经创建了您的对象

Answer 2

首先，你不应该做TopMost（）。save（），因为create函数做同样的事情。其次，只需确保数据库中的所有PinCode都附加了一个id。这可能是存在非空约束的完整性错误的原因。

Answer 3

我认为在这种情况下使用信号会更好（https://docs.djangoproject.com/en/1.9/topics/signals/ ），从view.py中删除代码并在models.py中添加信号：

from django.dispatch import receiver

class Pincode(models.Model):
    pincode = models.CharField("PinCode", max_length=6, null=False)
    geom = GeopositionField("Location")

class Topmost(models.Model):
    pincode = models.ForeignKey(Pincode, unique=True)
    rating_pincode = models.CharField("Total Rating points", max_length=255, null=True, blank=True)
    frequency = models.CharField("Number of user", max_length=255, null=True, blank=True)
    normalized_rank = models.FloatField(null=True, blank=True)

@receiver(post_save, sender=Pincode)
def create_topmost(sender, instance=None, created=False, **kwargs):
    if created:
       Topmost.objects.create(pincode=instance, rating_pincode="0", frequency="0", normalized_rank=0 )

Django IntegrityError NOT NULL约束失败

3 个答案: