Question

我要怎么做才能将pk分配为默认值？这不起作用：

from django.db import models

class TeamMember(models.Model):
    id = models.AutoField(primary_key=True)
    order_listing = models.IntegerField(default=id)

Answer 1

问题是直到将对象保存到数据库后才生成ID。但是，使用uuid可以解决此问题。

import uuid
from django.db import models

# unique id to be used as pk for TeamMember table.
unique_id = uuid.uuid4().hex


class TeamMember(models.Model):
    id = models.CharField(primary_key=True,
        default=unique_id, editable=False
    )
    order_listing = models.IntegerField(default=unique_id)

Answer 2

如果想在每次保存对象时将order_listing的值重置为id，则可以使用以下内容。

from django.db import models

class TeamMember(models.Model):
    id = models.AutoField(primary_key=True)
    order_listing = models.IntegerField(null=True, blank=True)


    def save(self, *args, **kw):
        self.order_listing = self.id
        return super(TeamMember, self).save(*args, **kw)

或下面的代码仅用于首次设置。

from django.db import models
from django.dispatch import receiver
from django.db.models.signals import post_save

class TeamMember(models.Model):
    id = models.AutoField(primary_key=True)
    order_listing = models.IntegerField(null=True, blank=True)

@receiver(post_save, sender=TeamMember)
def order_listing_update(sender, instance, created, **kwargs):
    if created:
        instance.order_listing = instance.id
        instance.save()

Django：在模型列中将模型的pk设置为默认值

2 个答案: