如果将其设置为True django，则生成唯一编号

Question

I'm trying to get my program to generate this unique number if confirmed == True.

class PurchaseOrder(models.Model):
    po_number = models.IntegerField(unique=True)
    confirmed = models.NullBooleanField(null=True)

 def save(self, *args, **kwargs):
    if not self.pk:
        self.po_number = self.validPONumber()
    super(PurchaseOrder, self).save(*args, **kwargs)

def validPONumber(self):
     low= 50000
     high =1000000
     random.seed()
     value = random.randrange(low, high)
     while 0 < len(PurchaseOrder.objects.filter(po_number=value)):
        value = random.randrange(low, high)
     return value

So, basically generate a po_number ONLY if confirmed == True. I've tried inserting the logic in random places, but it's generating errors. Where should I put it?

Answer 1

i think it could make sense to put it in the save method:

def save(self, *args, **kwargs):
    if not self.pk and self.confirmed:
        self.po_number = self.validPONumber()
    super(PurchaseOrder, self).save(*args, **kwargs)

This would specify that a record must be new and confirmed == True

Do you want it only to be generated from new records? Do you want the check to take place when you update a record? if so you could set it for every time the save method is called:

def save(self, *args, **kwargs):
    if self.confirmed:
        self.po_number = self.validPONumber()
    super(PurchaseOrder, self).save(*args, **kwargs)