django model 返回指定的字段

在Model中可以

class City(models.Model):
    CityID = models.IntegerField(unique=True, primary_key=True)
    CityName = models.CharField(max_length=300, blank=True)
    CityEnName = models.CharField(max_length=300, blank=True)

    city_list = []
    city_dict = {}
    using = 'citydb'  #使用指定的数据库

    class Meta:
        db_table = u'CityList'

    @staticmethod
    def getCityEnName(cityid):
        if cityid == 0:
            return u'All'
        if cityid < 0:
            return u'Unknown'
        try:
            cityenname = City.objects.using(City.using).values('CityEnName').filter(CityID=cityid)   #得到一个QuerySet  如：[{'CityEnName': u'beijing'}]
            cityenname = City.objects.using(City.using).get(CityID=cityid).CityEnName   #得到指定的字段值
        except ObjectDoesNotExist:
            return 'Unknown'
        return cityenname

在ModelManger中可以

class CityManager(models.Manager):
    def getCityEnNameByID(self, cityid):
        citylist = None
        if cityid is not None:
            citylist = super(CityManager, self).get_query_set() \  
              .values("cityenname") \
              .filter(cityid=cid)
        return citylist #得到[{'cityenname': u'beijing'}]的QuerySet

参照：

1. https://docs.djangoproject.com/en/dev/topics/db/models/

2. https://docs.djangoproject.com/en/dev/ref/models/querysets/

3. https://docs.djangoproject.com/en/dev/topics/db/queries/