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[英]Django - Filter objects based on their ForeignKey but with multiple choices?
[英]Django ForeignKey from multiple objects
我正在創建一個應用程序,用戶可以訂閱/關注網站的不同方面。
我正在構建將記錄所有這些訂閱的表。 我最初的直覺是制作一個訂閱表,它將列出訂閱的所有內容。 以下是我現在的計划方法:
class SubscriptionTypeCode(object):
CITY = '1'
REGION = '2'
COUNTRY = '3'
USER = '4'
SUBSCRIPTION_TYPE_CHOICES = (
(SubscriptionTypeCode.CITY, 'City'),
(SubscriptionTypeCode.REGION, 'Region'),
(SubscriptionTypeCode.COUNTRY, 'Country'),
(SubscriptionTypeCode.USER, 'User'),
)
class Subscription(models.Model):
subscriber = models.ForeignKey(User, related_name="subscriber")
subscription_type = models.CharField(max_length=4, choices=SUBSCRIPTION_TYPE_CHOICES)
subscription_to_user = models.ForeignKey(User, related_name="subscription_to_user", null=True, blank=True)
subscription_to_city = models.ForeignKey(City, null=True, blank=True)
subscription_to_country = models.ForeignKey(Country, null=True, blank=True)
subscription_to_region = models.ForeignKey(Region, null=True, blank=True)
created = models.DateTimeField(db_index=True, auto_now_add=True)
cancelled = models.DateTimeField(null=True, blank=True)
這應該工作,但我想知道這是否是最有效的方法。 每行將具有訂戶ID,然后是類型選擇,然后根據該行,其中一個subscription_to列將具有外部對象。
這是有效的,但在邏輯中需要很多if / else語句。 例如
def create_subscription(request, subscription_type, subscription_id):
subscription = Subscription.create(
subscriber = request.user,
subscription_type = subscription_type,
)
if subscription_type == SubscriptionTypeCode.REGION:
region = get_region(subscription_id)
subscription.subscription_to_region = region
elif subscription_type == SubscriptionTypeCode.CITY:
city = get_city(subscription_id)
subscription.subscription_to_city = city
elif subscription_type == SubscriptionTypeCode.COUNTRY:
country = get_country(subscription_id)
subscription.subscription_to_country = country
elif subscription_type == SubscriptionTypeCode.USER:
user = get_user(subscription_id)
subscription.subscription_to_user = user
subscription.save()
return subscription
有關如何簡化這個的任何想法? 或者這沒關系?
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