Trying to add 3rd nested serializer using django rest framework
how to add 3rd nested realation in given code -
models.py
class Category(models.Model):
cate_id = models.AutoField(primary_key=True)
cate_name = models.CharField(max_length=45)
class Meta:
managed = False
db_table = 'category'
class SubCategory(models.Model):
sub_cate_id = models.AutoField(primary_key=True)
sub_cate_name = models.CharField(max_length=45)
sub_fk = models.ForeignKey('Category', models.CASCADE, db_column='sub_fk')
class Meta:
managed = False
db_table = 'sub_category'
class Products(models.Model):
pro_id = models.AutoField(primary_key=True)
pro_name = models.CharField(max_length=45)
description = models.CharField(max_length=45, blank=True, null=True)
price = models.IntegerField()
quantity = models.IntegerField()
pro_cate_fk = models.ForeignKey('Category', models.CASCADE, db_column='pro_cate_fk')
pro_sub_fk = models.ForeignKey('SubCategory', models.CASCADE, db_column='pro_sub_fk')
image = models.CharField(max_length=205)
class Meta:
managed = False
db_table = 'products'
from rest_framework import serializers
from .models import Category,SubCategory,Products
class ProductsSerializer(serializers.ModelSerializer):
# x= ChildTable.objects.all().values
class Meta:
model = Products
fields = ('pro_id','pro_name','description','price','quantity','image')
class SubCategorySerializer(ProductsSerializer):
products_set = ProductsSerializer(many=True, read_only=True)
class Meta:
model = SubCategory
fields = ('sub_cate_name','sub_cate_id','products_set')
class CategorySerializer(SubCategorySerializer):
subcategory_set = ProductsSerializer(many=True, read_only=True,)
# pro_subcate_set = SubCategorySerializer(many=True, read_only=True)
class Meta:
model = Category
fields = ('cate_name','cate_id','subcategory_set')
Got this error while attempting -
Got AttributeError when attempting to get a value for field `pro_name` on serializer `ProductsSerializer`. The serializer field might be named incorrectly and not match any attribute or key on the `SubCategory` instance. Original exception text was: 'SubCategory' object has no attribute 'pro_name'.
Is it possible to connect 2 already connected serializer to another serializer?
Make a test and see if it works.
class CategorySerializer(serializers.ModelSerializer):
class Meta:
model = Category
fields = ('cate_id', 'cate_name')
class SubCategorySerializer(serializers.ModelSerializer):
class Meta:
model = SubCategory
fields = ('sub_cate_id', 'sub_cate_name', 'sub_fk')
def to_representation(self, instance):
response = super().to_represntation(instance)
response['sub_fk'] = CategorySerializer(instance.sub_fk).data
return response
class ProductSerializer(serializers.ModelSerializer):
class Meta:
model = Products
fields = ('pro_id', 'pro_name', 'description', 'price', 'quantity', 'pro_cate_fk', 'pro_sub_fk', 'image')
def to_representation(self, instance):
response = super().to_representation(instance)
response['pro_cate_fk'] = CategorySerializer(instance.pro_cate_fk).data
response['pro_sub_fk'] = ProductSerializer(instance.pro_sub_fk).data
return response
Related
I have this model that represents a bookmark or favorite. It has multiple foreign keys to other models. In the api I would like to pull in the data from each of the models that is referenced in the particular bookmark.
The model:
class Bookmark(models.Model):
marktype = models.CharField(max_length=10)
post = models.OneToOneField(Post, on_delete=models.CASCADE, null=True, blank=True)
question = models.OneToOneField(Question, on_delete=models.CASCADE, null=True, blank=True)
owner = models.ForeignKey(User, on_delete=models.CASCADE)
created_at = models.DateTimeField(auto_now_add=True, verbose_name="created at")
updated_at = models.DateTimeField(auto_now=True, verbose_name="updated at")
class Meta:
verbose_name = "bookmark"
verbose_name_plural = "bookmarks"
ordering = ["created_at"]
db_table = "bookmarks"
def __str__(self):
return "{}'s bookmark".format(self.owner.username)
I tried to use a SerializerMethodField but I get an error: 'NoneType' object has no attribute 'id'
Here is the serializer
class BookmarkSerializer(serializers.ModelSerializer):
post = serializers.SerializerMethodField()
question = serializers.SerializerMethodField()
class Meta:
model = Bookmark
fields = '__all__'
def get_post(self, obj):
obj = Post.objects.get(id=obj.post.id)
post = ShortPostSerializer(obj)
return post.data
def get_question(self, obj):
obj = Question.objects.get(id=obj.question.id)
question = ShortQuestionSerializer(obj)
return question.data
what am I doing wrong please?
You can update your serializer like the following (You can short it as you want or use your ShortQuestionSerializer as well instead of QuestionSerializer),
class QuestionSerializer(serializers.ModelSerializer):
class Meta:
model = Question
fields = '__all__'
class PostSerializer(serializers.ModelSerializer):
class Meta:
model = Post
fields = '__all__'
class BookmarkSerializer(serializers.ModelSerializer):
post = PostSerializer()
question = QuestionSerializer()
class Meta:
model = Bookmark
fields = '__all__'
I have 3 models which are related to each other via ManytoMany relation like this:
class DemandEvents(models.Model):
date = models.DateTimeField(blank=True, null=True)
quantity = models.IntegerField(default=0)
class DemandFlows(models.Model):
events = models.ManyToManyField(DemandEvents)
flow = models.ForeignKey(Flow, on_delete=models.CASCADE)
kit = models.ForeignKey(Kit, on_delete=models.CASCADE)
monthly_quantity = models.IntegerField(default=0)
class Demand(models.Model):
demand_flows = models.ManyToManyField(DemandFlows)
delivery_month = models.DateTimeField(blank=True, null=True)
owner = models.ForeignKey(User, on_delete=models.CASCADE)
I am trying to create the serializers for this but keep getting confused how to handle the multi-level nesting
Serializer.py
class DemandEventsSerializer(serializers.ModelSerializer):
class Meta:
model = DemandEvents
fields = "__all__"
class DemandFlowsSerializer(serializers.ModelSerializer):
class Meta:
model = DemandFlows
fields = "__all__"
class DemandSerializer(serializers.ModelSerializer):
demand_flows = DemandFlowsSerializer(many=True)
class Meta:
model = Demand
fields = "__all__"
def create(self, validated_data):
items_objects = validated_data.pop('form_list', None)
prdcts = []
for item in items_objects:
i = DemandFlows.objects.create(**item)
prdcts.append(i)
instance = Demand.objects.create(**validated_data)
instance.demand_flows.set(prdcts)
return instance
How do I add events data to this DemandFlows?
So I have two models here
class ProductType(models.Model):
product_type = models.CharField(max_length=50)
def __str__(self):
return self.product_type
class Product(models.Model):
product_name = models.CharField(max_length=50)
product_type = models.ForeignKey(ProductType, on_delete=models.CASCADE)
product_image = models.ImageField(blank=False, null=False, upload_to="products")
product_price = models.FloatField()
product_description = models.TextField(default="Product Description")
def __str__(self):
return self.product_name
And I have created an api using django-rest-framework to be consumed by the React frontend. However, when I try to get the product_type, it'd just give me a number instead of the name as shown below. So, how can I replace that when retrieving the data with Product.objects.all() in the view?
If you want to only show product_type instead of id you can use serializers.SerializerMethodField() in your ProductSerializer and with defining source in that method you can tell serializer to return your desired field.
Example:
class ProductSerializer(serializers.ModelSerializer):
product_type = serializers.SerializerMethodField(source='product_type__product_type')
class Meta:
model = Product
fields = ('id', 'product_name', 'product_image', 'product_price', 'product_description', 'product_type')
But if you want to serialize all the ProductType itself you can define a serializer for this model and then use this serializer in your ProductSerializer to serialize the whole object of ProductType.
Example:
class ProductTypeSerializer(serializers.ModelSerializer):
class Meta:
model = ProductType
fields = ('id', 'product_type',)
class ProductSerializer(serializers.ModelSerializer):
product_type = ProductTypeSerializer()
class Meta:
model = Product
fields = ('id', 'product_name', 'product_image', 'product_price', 'product_description', 'product_type')
The second solution is also known as nested serializers.
I have seen some related posts, but I am not sure what I need to do.
I have set up a view to serialize my test model which has nested models. I have set up the serializers, but I get the error "Got AttributeError when attempting to get a value for field Question on serializer TestSerializer.\nThe serializer field might be named incorrectly".
My Serializers:
class AnswerSerializer(serializers.ModelSerializer):
class Meta:
model = Answer
fields = ('id', 'number', 'text', 'iscorrect')
class QuestionSerializer(serializers.ModelSerializer):
answer = AnswerSerializer()
class Meta:
model = Question
fields = ('id', 'number', 'text', 'answer')
related_object = 'answer'
class TestSerializer(serializers.ModelSerializer):
question = QuestionSerializer()
class Meta:
model = Test
fields = ('id', 'name', 'question')
related_object = 'question'
My Models:
class Test(models.Model):
user = models.ForeignKey(User, on_delete=models.PROTECT)
name = models.CharField(max_length=255,default='',blank=False)
datecreated = models.DateTimeField(auto_now=True)
def __str__(self):
return self.name
class Question(models.Model):
test = models.ForeignKey(Test, on_delete=models.CASCADE)
text = models.CharField(max_length=255,default='',blank=False)
number = models.IntegerField()
def __str__(self):
return self.text
class Answer(models.Model):
question = models.ForeignKey(Question, on_delete=models.CASCADE)
text = models.CharField(max_length=255,default='',blank=False)
number = models.IntegerField()
iscorrect = models.BooleanField(default=False)
def __str__(self):
return self.text
The call from the view:
serializer = TestSerializer(test, many=True)
You have set the related_name in the foreign key other wise default related name is {model_name}_set.
class Question(models.Model):
test = models.ForeignKey(Test, on_delete=models.CASCADE, related_name='questions')
text = models.CharField(max_length=255,default='',blank=False)
number = models.IntegerField()
def __str__(self):
return self.text
in serializer you can access that fields
class TestSerializer(serializers.ModelSerializer):
questions = QuestionSerializer(many=True)
class Meta:
model = Test
fields = ('id', 'name', 'question')
related_object = 'question'
I want to add json data from the listserializer to the DetailSerializer class. The serializer looks something like this:
serializer.py
class ListSerializer(serializers.ModelSerializer):
class Meta:
model = Fastest_laps
fields = '__all__'
class DetailSerializer(serializers.ModelSerializer):
listserializer = ListSerializer( read_only=True, many=True)
class Meta:
model = Driver
fields =
('place_of_birth','driver','listserializer','picture')
But i dont really see the data once i view it, i only see the detailserializer data( Driver model)
class Fastest_laps(models.Model):
driver_name = models.CharField(max_length=25, null=True)
grand_prix = models.CharField(max_length=15, blank=True)
car_model = models.CharField(max_length=50)
time_taken = models.CharField(blank=True, max_length=8)
def __str__(self):
return self.driver_name
class Driver(models.Model):
place_of_birth = models.CharField(max_length=25)
driver = models.ForeignKey(Fastest_laps,
db_column='driver_name')
picture = models.ImageField(blank=True, null=True)
def __str__(self):
return str(self.driver)
api.py
class FastLapsSet(ModelViewSet):
queryset = Fastest_laps.objects.all()
serializer_class = ListSerializer
class DriverSet(ModelViewSet):
queryset = Driver.objects.all()
serializer_class = DetailSerializer
you should rename your property as model name field:
class DetailSerializer(serializers.ModelSerializer):
driver = ListSerializer(read_only=True)
# ^^^
class Meta:
model = Driver
fields =
('place_of_birth','driver','driver','picture')
or add the source attribute:
class DetailSerializer(serializers.ModelSerializer):
listserializer = ListSerializer(source='driver', read_only=True)
#^^^^
class Meta:
model = Driver
fields =
('place_of_birth','driver','listserializer','picture')