Python模型Foreignkey向后关系

Question

我需要通过大陆模式的“国家”属性来拯救一个大陆的所有国家。我该怎么做？ 谢谢。你知道吗

from django.db import models

class Continent(models.Model):
    name = models.CharField(max_length=255, unique = True)
    code = models.CharField(max_length=255, unique = True)
    allCountries = models.Manager()
    countries = ???

class Country(models.Model):
    name = models.CharField(max_length=255 )
    capital = models.CharField(max_length=255 )
    code = models.CharField(max_length=255, unique = True)
    population = models.PositiveIntegerField()
    area = models.PositiveIntegerField()
    continent = models.ForeignKey(Continent)

Answer 1

要获得某个大陆的所有国家，您必须执行以下操作：

continent = Continent.objects.get(name='Europe')
countries = continent.country_set.all() # returns all countries from Europe

您不需要在“大陆”中添加“国家”字段