Question

我正在尝试使用以下序列化程序进行POST -

class VariablePUTSerializer(serializers.ModelSerializer):
    owner_id = serializers.SerializerMethodField('get_owner_id')

    class Meta:
        model = Varmst
        resource_name = 'varmst'
        fields = ('varmst_id', 'varmst_type', 'varmst_name', 'varmst_value', 'varmst_desc',
                'varmst_public', 'owner_id', 'varmst_lstchgtm', 'varmst_publish', 'varmst_readonly',
                'varmst_calc', 'varmst_starttype', 'varmst_startdt', 'varmst_startcal',
                'varmst_offsets', 'varmst_lstval')

    def transform_varmst_id(self, obj, value):
        maxid = Varmst.objects.latest('varmst_id').varmst_id
        if Varmst.objects.filter(varmst_name=obj.varmst_name).exists():
            obj.varmst_id = Varmst.objects.filter(varmst_name=obj.varmst_name).values_list('varmst_id')[0]
            return obj.varmst_id
        else:
            obj.varmst_id = maxid + 1
            return obj.varmst_id

    def get_owner_id(self, obj):
        obj.owner_id = Owner.objects.filter(owner_name='Operations').values_list('owner_id')[0][0]
        return obj.owner_id

尝试POST数据时会出现以下错误 -

Exception Type: ValueError at /deploy/variable/
Exception Value: Cannot assign "786": "Varmst.owner_id" must be a "Owner" instance.

Varmst.owner_id是对Owner.owner_id的FK引用，我检查了数据库，并且该值（786）确实存在，所以我不确定为什么将它传递给序列化程序会导致它失败。

下面的完整追溯 -

Traceback:
File "D:\Python27\lib\site-packages\django\core\handlers\base.py" in get_response
  112.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "D:\Python27\lib\site-packages\django\views\generic\base.py" in view
  69.             return self.dispatch(request, *args, **kwargs)
File "D:\Python27\lib\site-packages\django\views\decorators\csrf.py" in wrapped_view
  57.         return view_func(*args, **kwargs)
File "D:\Python27\lib\site-packages\rest_framework\views.py" in dispatch
  400.             response = self.handle_exception(exc)
File "D:\Python27\lib\site-packages\rest_framework\views.py" in dispatch
  397.             response = handler(request, *args, **kwargs)
File "D:\Tidal\API\views.py" in put
  343.             return HttpResponse(serializer.data, status=status.HTTP_201_CREATED)
File "D:\Python27\lib\site-packages\rest_framework\serializers.py" in data
  573.                 self._data = [self.to_native(item) for item in obj]
File "D:\Python27\lib\site-packages\rest_framework\serializers.py" in to_native
  351.             value = field.field_to_native(obj, field_name)
File "D:\Python27\lib\site-packages\rest_framework\fields.py" in field_to_native
  1035.         value = getattr(self.parent, self.method_name)(obj)
File "D:\Tidal\API\serializers.py" in get_owner_id
  162.         obj.owner_id = Owner.objects.filter(owner_name='Operations').values_list('owner_id')[0][0]
File "D:\Python27\lib\site-packages\django\db\models\fields\related.py" in __set__
  339.                                  self.field.name, self.field.rel.to._meta.object_name))

Exception Type: ValueError at /deploy/variable/
Exception Value: Cannot assign "786": "Varmst.owner_id" must be a "Owner" instance.

以下是我的模特 -

class Owner(models.Model):
    owner_id = models.IntegerField(primary_key=True, db_column='owner_id')
    owner_type = models.SmallIntegerField(blank=True, null=True)
    owner_name = models.CharField(max_length=30, blank=True)
    owner_allagents = models.CharField(max_length=1, blank=True) 
    class Meta:
        managed = False
        db_table = 'owner'

class Varmst(models.Model):
    varmst_id = models.IntegerField(primary_key=True, db_column='varmst_id')
    varmst_type = models.SmallIntegerField(blank=True, null=True)
    varmst_name = models.CharField(max_length=30, blank=True)
    varmst_value = models.TextField(blank=True)
    varmst_desc = models.TextField(blank=True)
    varmst_public = models.CharField(max_length=1, blank=True)
    owner_id = models.ForeignKey(Owner, db_column='owner_id')
    class Meta:
        managed = False
        db_table = 'varmst'

Answer 1

凯文克里斯托弗亨利解决了以下问题 -

如果您为字段所有者命名，那么db_column将自动为owner_id。如果需要，请随意明确db_column，但将该字段命名为owner_id。否则你将失去区分Django模型实例和整数id的能力。

异常值：无法分配“786”：“Varmst.owner_id”必须是“所有者”实例

1 个答案: