在Django模型中继承元类

Question

作为新手，我有一个问题，我正在寻找与Django类中的元类继承相关的概念。以下是模型，如果有人能帮助我，我将不胜感激。

class Base(models.Model):
    code = AutoSlugField(_("Slug"), max_length=128, unique=True,
                         populate_from='name')
    name = models.CharField(_("Name"), max_length=128, unique=True)
    description = models.TextField(_("Description"), blank=True)
    countries = models.ManyToManyField('Country',
                                       blank=True, verbose_name=_("Countries"))
    is_discounted = False
    class Meta:
        app_label = 'shipping'
        ordering = ['name']
        verbose_name = _("Shipping Method")
        verbose_name_plural = _("Shipping Methods")


class OrderAndItemCharges(Base):
    price_per_order = models.DecimalField(
        _("Price per order"), decimal_places=2, max_digits=12,
        default=D('0.00'))
    price_per_item = models.DecimalField(
        _("Price per item"), decimal_places=2, max_digits=12,
        default=D('0.00'))
    free_shipping_threshold = models.DecimalField(
        _("Free Shipping"), decimal_places=2, max_digits=12, blank=True,
        null=True)
    class Meta(Base.Meta):
        app_label = 'shipping'
        verbose_name = _("Order and Item Charge")
        verbose_name_plural = _("Order and Item Charges")

回溯：

    class OrderAndItemCharges(Base):
  File "C:\Users\AliKhan\supermarekt\market\shipping\models.py", line 46, in Or
derAndItemCharges
    class Meta(Base.Meta):
AttributeError: type object 'Base' has no attribute 'Meta'

我已经更改了类导入行为，以克服如下问题。这可能是问题的根源。原因是我需要简化商店仪表板应用程序的代码。因此，我导入了用于导入Django类的默认Django源，并对其进行了如下更改：

from django.apps.config import MODELS_MODULE_NAME
def get_class(module_label, classname):
    return get_classes(module_label, [classname])[0]
def get_classes(module_label, classnames):
    if not module_label:
        raise ValueError(
            "Module Does Not Exists")

    market_module_label = "%s" % (module_label)
    market_module = _import_module(market_module_label, classnames)
    return _pluck_classes([market_module], classnames)
def _import_module(module_label, classnames):
    try:
        return __import__(module_label, fromlist=classnames)
    except ImportError:
        __, __, exc_traceback = sys.exc_info()
        frames = traceback.extract_tb(exc_traceback)
        if len(frames) > 1:
            raise

文件名是loading.py，我是从Django Oscar那里学来的。不过，我做了一些小改动，以适应我的需要。问题可能就在这里。请协助

Answer 1

您应该声明Base类抽象，以便将其Meta类作为属性访问。

class A(models.Model):
    class Meta:
        app_label='yourapp'
        abstract=True

class B(A):
    class Meta(A.Meta):
        db_table='yourtable'

相关文件：https://docs.djangoproject.com/en/1.10/topics/db/models/#meta-inheritance