django结合了两种不同基础模型的查询

时间:2014-03-17 15:10:47

标签: python django django-queryset

我有两个不同的不同查询集,我想要将两个查询集联合起来

 q1 = tbl_nt_123.objects.values_list('id', 'value', 'geometry').filter(restriction='height')\
        .exclude(condition_id__in=tbl_conditions.objects.filter(version_id=5).values_list('condition_id',flat=True))

 q2 = tbl_network.objects.all().filter(Q(name="height"), Q(state_id=1) | Q(state_id=2)).values_list('id', 'value', 'geometry');

我试过这个功能

  

queryset =(q1)| (Q2)

面对此错误'django将查询组合在两个不同的基础模型上

所以我尝试了另外两个函数,但这些也抛出同样的异常'list'对象没有属性'model''

  

queryset = list(q1)+ list(q2)

     

queryset = chain(q1,q2)

从此处更新我的问题

class tbl_nt_123(models.Model):
    condition_id = models.IntegerField(blank=True, null=True)
    value = models.FloatField(blank=True, null=True)
    geometry = models.GeometryField(blank=True, null=True)
    class Meta:
        db_table = u'tbl_nt_123'

class tbl_conditions(models.Model):
    condition_id = models.IntegerField()
    version_id = models.ForeignKey(LookupNavteqversion)
    class Meta:
        db_table = u'tbl_conditions'


class tbl_network(models.Model):
    name = models.CharField(max_length=50, blank=True)
    value = models.FloatField()
    state_id = models.IntegerField(null=True, blank=True)
    geometry = models.GeometryField(null=True, blank=True)
    objects = models.GeoManager()

    class Meta:
        db_table = u'tbl_network'

    def __unicode__(self):
        return '%s' % self.name

class tbl_networkSerializer(serializers.GeoModelSerializer):
    class Meta:
        model = tbl_network
        fields = ('id', 'value', 'geometry')

此处查看文件

   class NetworkViewSet(viewsets.ModelViewSet):

      q1 = tbl_nt_123.objects.values_list('id', 'value', 'geometry').filter(restriction='height')\
            .exclude(condition_id__in=tbl_conditions.objects.filter(version_id=5).values_list('condition_id',flat=True))

     q2 = tbl_network.objects.all().filter(Q(name="height"), Q(state_id=1) | Q(state_id=2)).values_list('id', 'value', 'geometry');

     queryset = list(chain(q1, q2))

     serializer_class = tbl_networkSerializer

但这两个函数都没有返回查询集类型记录。

我想查询集类型为tbl_network(q2)

我该怎么做?

1 个答案:

答案 0 :(得分:0)

由于django不支持混合查询集(它们必须只对应一个模型),我建议你使用不同的方法:模型继承或FK。

class MyGeometry(models.Model):
    value = ...
    geometry = ...

class tbl_nt_123(MyGeometry):
    condition_id = models.IntegerField(blank=True, null=True)
    value = models.FloatField(blank=True, null=True)
    geometry = models.GeometryField(blank=True, null=True)

class tbl_network(MyGeometry):
    name = models.CharField(max_length=50, blank=True)
    state_id = models.IntegerField(null=True, blank=True)
    objects = models.GeoManager()

...
#you should also rewrite your queries and then merge them.
#remember that inheritance let's you access parent_links and children_links
#between models.
#your query 1 should be like this one below, and a similar approach for query2.
#since they will be of the same type, you can merge them. Later, you can access
#their children links ('tbl_nt_123' and 'tbl_network), being aware that upon non-existance those links will throw DoesNotExist, upon model iteration.

q1 = MyGeometry.objects.values_list('id', 'value', 'geometry').select_related('tbl_nt_123').filter(tbl_nt_123__restriction='height')\
.exclude(condition_id__in=tbl_conditions.objects.filter(version_id=5).values_list('condition_id',flat=True))

修改:不知道你在哪里获得了限制'字段,因为它没有出现在模型中,但我还是把它放在"尊重"你的代码(假设那里没有错误)。

编辑2 :一旦查询属于同一模型(例如q1 + q2),您就可以将它们与您之前尝试过的方法合并