Django OneToOneField在克隆过程中不允许空值

Question

假设我有以下型号：

class Cart(models.Model):
  uuid = models.CharField()

class Order(models.Model):
  cart = models.OneToOneField('Cart')

当我想要克隆购物车时：

cart.id = None
cart.order = None
cart.save()

我收到此错误：

ValueError: Cannot assign None: "Cart.order" does not allow null values.

Answer 1

试试这个：

class Cart(models.Model):
    uuid = models.CharField()

class Order(models.Model):
    cart = models.OneToOneField('Cart',blank=True,null=True)