CODEWITHSUNDEEP
pythondjangoserializationdjango-rest-framework
Ayushi Rajguru
Ayushi Rajguru

Reputation: 113

AttributeError with Django Rest nested serializer

I'm following the Django Rest documentation for writing nested serializer but it is giving me attribute error.

Here are my models:

class Objects(TimeStampModel):
    projects = models.ForeignKey(Projects,related_name='proj_obj',on_delete=models.CASCADE)
    object_name = models.CharField(max_length=50)
    object_description = models.TextField()
    object_main_table = models.CharField(max_length=50)
    object_primary_key = models.CharField(max_length=50)
    object_age_field = models.CharField(max_length=50)
    date_format = models.CharField(max_length=50)

    def __str__(self):
        return self.object_name


class ObjectDefinition(TimeStampModel):
    ATTRIBUTE = 'Attribute'
    RELATION = 'Relation'
    TYPE_CHOICES = (
        (ATTRIBUTE, 'Attribute'),
        (RELATION, 'Relation'),
    )
    obj = models.ForeignKey(Objects,related_name='obj_def',on_delete=models.CASCADE)
    from_table = models.CharField(max_length=50)
    from_table_field = models.CharField(max_length=50)
    to_table = models.CharField(max_length=50)
    to_table_field = models.CharField(max_length=50)
    relation_type = models.CharField(max_length=50,choices=TYPE_CHOICES)
    relation_sequence = models.CharField(max_length=50)
    value_field = models.CharField(max_length=50, blank=True, null=True)

Here is my serializers.py snippet:

class ObjectDefinitionSerializer(serializers.ModelSerializer):

    class Meta:
        model = ObjectDefinition
        fields = ('from_table','from_table_field','to_table','to_table_field','relation_type','value_field')

class ObjectSerializer(serializers.ModelSerializer):
    definition = ObjectDefinitionSerializer(many=True)
    object_description = serializers.CharField(required=False, allow_null=True, allow_blank=True
        )

    class Meta:
        model = Objects
        fields = ('projects','object_name','object_description','object_main_table','object_primary_key','object_age_field','date_format','definition')

    def validate(self, data, *args, **kwargs):
        date_format = data.get('date_format')
        if date_format not in ['YYYYMMDD', 'DDMMYYYY']:
            msg = ('Date format is incorrect')
            raise serializers.ValidationError({'error_msg': msg})
        return super(ObjectSerializer, self).validate(data, *args, **kwargs)

    def create(self, validated_data):
        definition_data = validated_data.pop('definition')
        obj = Objects.objects.create(**validated_data)
        for data in definition_data:
            ObjectDefinition.objects.create(obj=obj, **data)
        return obj

My views.py:

class CreateObject(CreateAPIView):
    permission_classes = (IsAuthenticated,)
    serializer_class = ObjectSerializer

After hitting POST, objects.create works fine for both the models but at return obj, it throws me this error:

Exception Value:

Got AttributeError when attempting to get a value for field definition on serializer ObjectSerializer. The serializer field might be named incorrectly and not match any attribute or key on the Objects instance. Original exception text was: 'Objects' object has no attribute 'definition'.

What am I missing?

Upvotes: 1

Views: 1393

Answers (1)

Linovia
Linovia

Reputation: 20996

The ObjectDefinition.obj's related_name is obj_def which doesn't match your serializer.

You can fix that by providing the source argument:

definition = ObjectDefinitionSerializer(source='obj_def', many=True)

Upvotes: 2

Related Questions