I want to get all prodcut table values with join product_ratings table. I did somthing like this but this code give me AttributeError. So I did product_ratings = ProductRatingSerializer(many=True)
in product serializer and used this value in the field, but it's not working:
The full error message:
Got AttributeError when attempting to get a value for field `product_ratings` on serializer `ProductSerializer`.
The serializer field might be named incorrectly and not match any attribute or key on the `Product` instance.
Original exception text was: 'Product' object has no attribute 'product_ratings'.
view :
class StoreApiView(mixins.CreateModelMixin, generics.ListAPIView):
lookup_field = 'pk'
serializer_class = ProductSerializer
def get_queryset(self):
qs = Product.objects.all()
query = self.request.GET.get('q')
if query is not None:
qs = qs.filter(
Q(title__icontains=query) |
Q(description__icontains=query)
).distinct()
return qs
its serializer classes:
class ProductRatingSerializer(ModelSerializer):
class Meta:
model = Product_ratings
fields = [
'p_id',
'commenter',
'comment',
'rating',
'created_date',
]
read_only_fields = ['p_id']
class ProductSerializer(ModelSerializer):
product_ratings = ProductRatingSerializer(many=True)
author = serializers.SerializerMethodField()
def get_author(self, obj):
return obj.author.first_name
class Meta:
model = Product
fields = [
'product_id',
'author',
'category',
'title',
'description',
'filepath',
'price',
'created_date',
'updated_date',
'product_ratings',
]
read_only_fields = ['product_id', 'created_date', 'updated_date', 'author']
related model class :
class Product(models.Model):
product_id = models.AutoField(primary_key=True)
author = models.ForeignKey(User, on_delete=models.CASCADE, db_index=True)
category = models.ForeignKey(Category, on_delete=models.CASCADE, to_field='cat_id')
title = models.CharField(max_length=120)
description = models.TextField(null=True, blank=True)
price = models.CharField(max_length=50, null=True, blank=True)
filepath = models.CharField(max_length=100, null=True, blank=True)
created_date = models.DateTimeField(auto_now_add=True)
updated_date = models.DateTimeField(auto_now=True)
class Product_ratings(models.Model):
p_id = models.ForeignKey(Product, on_delete=models.CASCADE, to_field='product_id')
commenter = models.ForeignKey(User, on_delete=models.CASCADE)
comment = models.CharField(max_length=200, null=True, blank=True)
rating = models.IntegerField(null=True, blank=True)
created_date = models.DateTimeField(auto_now_add=True)
The default reverse lookup name for ForeignKey is <mode>_set or product_ratings_set in your case, so you need to replace the product_ratings field in the ProductSerializer with product_ratings_set :
class ProductSerializer(ModelSerializer):
product_ratings_set = ProductRatingSerializer(many=True)
class Meta:
model = Product
fields = [ ... 'product_ratings_set' ] You can also add related_name='product_ratings' to the ForeignKey of the model to change the reverse lookup name, in this case you don't need to change the serializer too much:
class Product_ratings(models.Model): p_id = models.ForeignKey(Product, on_delete=models.CASCADE, to_field='product_id', related_name='product_ratings')in my case I had to return just single object from my views.py but I was returning queryset, so changing objects.filter to objects.get fixed the issue for me
Selected answer doesn't work for me. However following way worked:
product_ratings = ProductRatingSerializer(many=True)
Also remember to put product_ratings in related_name field like this:
p_id = models.ForeignKey(Product, on_delete=models.CASCADE, to_field='product_id', related_name='product_ratings')
Here is how Meta class looks:
class Meta:
model = Product
fields = [
...
'product_ratings'
]