繼承Django模型中的元類

Question

我有一個新手問題，我正在尋找與Django類中的Meta類繼承相關的概念。以下是模型，如果有人能幫助我，我將不勝感激。

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' 

我已經改變了類導入行爲得到了與像以下。這可能會導致問題。原因是我需要緩解店鋪儀表板應用程序的代碼。於是我進口Django缺省的源導入Django的類和改變它象下面這樣：

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，我學會了從Django的奧斯卡獎。不過，我做了些微的修改，以適應我的需要。所以問題可能在這裏。請協助

Answer 1

您應該聲明您的Base類抽象以訪問它的Meta類作爲屬性。

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

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

相關文章：https://docs.djangoproject.com/en/1.10/topics/db/models/#meta-inheritance