Django 重复主键

Question

我有一个表单可以在提交后创建一个具有相同先前 ID 的对象。怎么每次都把uuid改成随机的？

class TbTerminalPermission(models.Model):
    id = models.CharField(
        primary_key=True, default=str(uuid.uuid4()).replace('-', ''), max_length=60)
    terminal = models.ForeignKey(
        'app.TbTerminal', on_delete=models.CASCADE, db_column='ter_id')
    user = models.ForeignKey(
        TbUser, on_delete=models.CASCADE, db_column='user_id')

    class Meta:
        managed = False
        db_table = 'tb_terminal_permission'
        unique_together = ('id', 'terminal', 'user')

class TbTerminalPermissionForm(forms.ModelForm):

    class Meta:
        model = TbTerminalPermission
        fields = ['user', 'terminal']

    def __init__(self, user, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.user = user
        if self.user:
            self.fields['user'].queryset = TbUser.objects.filter(
                id=self.user.id)
            self.fields['terminal'].queryset = TbTerminal.objects.exclude(
                tbterminalpermission__user=self.user).filter(customer=self.user.customer)

错误

Exception Value:    
(1062, "Duplicate entry 'ea870f29ec124e39aa5251b0862635f3' for key 'PRIMARY'")

Answer 1

如果您与：

一起工作

id = models.CharField(
    primary_key=True,
    <strong>default=str(uuid.uuid4()).replace('-', '')</strong>,
    max_length=60
)

然后Python将计算str(uuid.uuid4()).replace('-', '')一次，并在每次必须生成主键时使用它作为默认值，因此如果您第二次保存一个对象，将会有碰撞。

您应该定义一个生成字符串的函数，并将 reference 作为默认值传递给该函数，因此：

def <strong>gen_pk_perm</strong>():
    return str(uuid.uuid4()).replace('-', '')

class TbTerminalPermission(models.Model):
    id = models.CharField(primary_key=True, default=<strong>gen_pk_perm</strong>, max_length=60)
    # …

Answer 2

此 ID 替换解决了问题

id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)

Django 重复主键

Django duplicate primary keys

python

django

django-models

django-forms