CODEWITHSUNDEEP
pythondjangodjango-rest-frameworkdjango-serializer
ScienceNoob
ScienceNoob

Reputation: 231

Serializes ManyToMany relations in Django Rest Framework

I want to serializing ManyToMany fields. So, in the response for tje Application model should also the band and the band description listed. But I've got the following error message:

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

Anyone who knows why it doesnt work?

models.py

class Band(models.Model):
    """Database models for satellit's bands information"""

    band = models.CharField(max_length=3)
    description = models.CharField(max_length=255)
    in_satellite = models.ForeignKey('Satellite', on_delete=models.PROTECT, blank=True, null=True)
    wavelength = models.DecimalField(max_digits=4, decimal_places=0, default='0', help_text='Central wavelength (nm)')
    resolution = models.DecimalField(max_digits=4, decimal_places=0, default='0', help_text='Spatial resolution (m)')

    def __str__(self):
        return '%s | %s' % (self.in_satellite, self.band)


class Satellite(models.Model):
    """Database models for satellite information"""

    name = models.CharField(max_length=255)
    accr = models.CharField(max_length=3)
    operator = models.CharField(max_length=255, default='European Space Agency')

    def __str__(self):
        return self.name


class Indice(models.Model):
    """Database models for index information"""

    name = models.CharField(max_length=255)
    accr = models.CharField(max_length=10)
    description = models.TextField(max_length=255, blank=True, null=True)
    satellite_to_use = models.ForeignKey('Satellite', on_delete=models.PROTECT, blank=True, null=True)
    needed_bands = models.ManyToManyField(Band)

    def __str__(self):
        return self.name


class Application(models.Model):
    """Database models for application information"""

    name = models.CharField(max_length=255)
    description = models.TextField(max_length=255, blank=True, null=True)
    indice_to_use = models.ForeignKey('Indice', on_delete=models.PROTECT, blank=True, null=True)

    def __str__(self):
        return self.name

serializers.py

class BandSerializer(serializers.ModelSerializer):

    class Meta:
        model = Band
        fields = ['band', 'description', ]

class OsdSerializer(serializers.ModelSerializer):
    bands = BandSerializer()

    class Meta:
        model = Application
        fields = ['name', 'description', 'bands',]

views.py

class OsdView(APIView):
    def get(self, request):
        applications = Application.objects.all()
        serializer = OsdSerializer(applications, many=True)
        return Response({"Your open space data:": serializer.data})

Upvotes: 0

Views: 94

Answers (2)

drec4s
drec4s

Reputation: 8077

IIUC, you need to change the OsdSerializer to specify the relation you want to include in the serialized data:

bands = BandSerializer(source='indice_to_use.needed_bands', many=True)

Upvotes: 2

Tarun Adavani
Tarun Adavani

Reputation: 121

Your code is correct but here i don't see any relation between two of your models Band and Application.

I think you might need to find some relation between Band model and Application model only then and then you will get the band object in output associated with corresponding application object.

Upvotes: 1

Related Questions