在Django模型中如何进行原子增量

Question

如何在模型中创建原子增量

class IpadCode(models.Model):
    """
    code = string
    """
    code = models.CharField(max_length=6, blank=True, null=True)
    submission_index = models.PositiveIntegerField(default=0)

    CODE_FIELD = 'code'

    class Meta:
        verbose_name = 'ipad code'
        verbose_name_plural = 'ipad codes'

    @classmethod
    def increment_counter(self, code):
        pass

    def get_code(self):
        """
        :return: return code for this winner
        """
        return getattr(self, self.CODE_FIELD)

    def __str__(self):
        return self.get_code()

我需要跟踪已保存了多少code并计算在内，以便以后如果满足特定条件的用户可以在视图重定向用户中看到。

Answer 1

# You have to use 'AutoField' attribute of models for your 'code' field

class IpadCode(models.Model):
    """
    code = string
    """
    code = models.AutoField(primary_key=True)
    submission_index = models.PositiveIntegerField(default=0)

    CODE_FIELD = 'code'

    class Meta:
        verbose_name = 'ipad code'
        verbose_name_plural = 'ipad codes'

    @classmethod
    def increment_counter(self, code):
        pass

    def get_code(self):
        """
        :return: return code for this winner
        """
        return getattr(self, self.CODE_FIELD)

    def __str__(self):
        return self.get_code()