I have a very simple question and I'm surprised it hasn't been asked before on this website.
I have the two following models:
# models.py
class Film(models.Model):
id = models.AutoField(primary_key=True)
title = models.CharField(max_length=150)
genre = models.ManyToManyField(Genre)
class Genre(models.Model):
id = models.AutoField(primary_key=True)
name = models.CharField(max_length=100, unique=True)
I need to make an API that gets 2 integers, id of movie and id of genre, and adds the said genre to the movie. seems very simple but I don't know how I could do this. I could really use the help.
You might want this:
class GenreSerializer(serializers.ModelSerializer):
class Meta:
model = Genre
fields = ('name', 'id')
class FilmSerializer(serializers.ModelSerializer):
genre = GenreSerializer(many=True, read_only=False)
class Meta:
model = Film
fields = ('name', 'id', 'genre')
def update(self, instance, validated_data):
genres_data = validated_data.pop('genre')
instance = super(FilmSerializer, self).update(instance, validated_data)
for genre_data in genres_data:
genre_qs = Genre.objects.filter(name__iexact=genre_data['name'])
if genre_qs.exists():
genre = genre_qs.first()
else:
genre = Genre.objects.create(**genre_data)
instance.genre.add(genre)
return instance
Related
Let us imagine that I have two models.
First model contains curse details and user that created this course
class Course(models.Model):
course_name = models.CharField(max_length=100, null=False)
description = models.CharField(max_length=255)
user_profile = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
and my second model is:
class Lesson(models.Model):
course = models.OneToOneField(Course, on_delete=models.CASCADE) #
# inside the course I want my APIVIEW to list only the courses that current user created.
# OnetoOne relationship does not solve the problem.
status = models.CharField(choices=STATUS, null=False, default=GOZLEMEDE,max_length=20)
tariffs = models.FloatField(max_length=5,null=False,default=0.00)
continues_off = models.CharField(max_length=2)
user_profile = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
My serializers for both Models:
class LessonSerializer(serializers.ModelSerializer):
class Meta:
model = models.Lesson
fields = ('course', 'status', 'tariffs', 'continues_off', 'user_profile')
def create(self, validated_data):
lesson = models.Lesson.objects.create(
course = validated_data['course'],
status = validated_data['status'],
tariffs=validated_data['tariffs'],
continues_off=validated_data['continues_off'],
user_profile=validated_data['user_profile']
)
return lesson
class CourseSerializer(serializers.ModelSerializer):
"""Serializers Course content"""
class Meta:
model = models.Course
fields = '__all__'
def create(self,validated_data):
course = models.Course.objects.create(
course_name = validated_data['course_name'],
description=validated_data['description'],
user_profile=validated_data['user_profile']
)
return course
My Viewset:
class LessonViewset(viewsets.ModelViewSet):
model = models.Lesson
serializer_class = serializers.LessonSerializer
authentication_classes = (SessionAuthentication,)
permission_classes = (IsAuthenticated,BasePermission,)
def get_queryset(self):
user_current = self.request.user.id
return models.Lesson.objects.filter(user_profile=user_current)
How can I get the desired result. I want to get the courses for the current user and show them as a dropdown list in my API view. Just only the courses that user created should be in the dropdown list not all.
OnetoOne relationship gives all results of course table.
i think change your view code to :
def get_queryset(self,id):
return model.objects.filter(user_profile=id)
#You do not need to call it again when you put the Lesson on the model
\
I have a serializer in my Django app that is meant for updating a nested object. Updating works, but I'm facing another problem: I can't delete objects that are not in validated_data['events] because I don't have the id to be compared with my instance id's.
For reference, these are my Models:
class Plan(models.Model):
planId = models.CharField(primary_key=True, max_length=100, unique=True)
name = models.CharField(max_length=200)
class PlanEvent(models.Model):
plan = models.ForeignKey(Plan, on_delete=models.CASCADE)
id = models.CharField(primary_key=True, max_length=100, unique=True, blank=False, null=False)
done = models.BooleanField()
title = models.CharField(max_length=100, blank=True)
This is my PlanEventUpdateSerializer:
class PlanEventUpdateSerializer(serializers.ModelSerializer):
class Meta:
model = PlanEvent
fields = ('done', 'title')
Is there some way to include the id, so I could compare the id's like this in my update method:
class PlanUpdateSerializer(serializers.ModelSerializer):
events = PlanEventUpdateSerializer(many=True)
class Meta:
model = Plan
fields = ('name',)
....
def update(self, instance, validated_data):
events_validated_data = validated_data.pop('events')
events = (instance.events.all())
events = list(events)
event_ids = [item['id'] for item in events_validated_data]
for event in events:
if event.id not in event_ids:
event.delete()
I found a solution. I defined the id as a optional field in the serializer and then I was able to include it in the fields. Sending POST and PUT requests works now and I'm also able to delete objects when updating:
class PlanEventUpdateSerializer(serializers.ModelSerializer):
id = serializers.CharField(source='pk', required=False)
class Meta:
model = PlanEvent
fields = ('id', 'done', 'title')
I want to post a movie into the collection's movie field( list of movies).
I define the model as
class Movie(models.Model):
# collection = models.ForeignKey(Collection, on_delete = models.CASCADE) #, related_name='reviews'
title = models.CharField(max_length=200)
description = models.CharField(max_length=200)
genres = models.CharField(max_length=200)
uuid = models.CharField(max_length=200)
def __str__(self):
return self.title
class Collection(models.Model):
title = models.CharField(max_length=200)
uuid = models.CharField(max_length=200, primary_key = True)
description = models.CharField(max_length=200)
movie = models.ForeignKey(Movie, on_delete = models.CASCADE)
def __str__(self):
return self.title
this is how i am using the viewset
class CollectionViewSet(viewsets.ModelViewSet):
queryset = models.Collection.objects.all()
serializer_class = serializers.CollectionSerializer
but i am not able to enter values for the movie field
enter image description here
also my serializer
class CollectionSerializer(serializers.ModelSerializer):
class Meta:
model = Collection
fields = '__all__'
By default, DRF will represent the relationship with a PrimaryKeyRelatedField, thus expecting a movie ID.
To achieve what you want (create an instance of movie with a collection), you need to overwrite the foreign key field in your serializer with your own Movie serializer.
class MovieSerializer(serializers.ModelSerializer):
class Meta:
model = Movie
fields = '__all__'
class CollectionSerializer(serializers.ModelSerializer):
movie = MovieSerializer()
class Meta:
model = Collection
fields = '__all__'
def create(self, validated_data):
movie = validated_data.pop('movie')
movie = Movie .objects.create(**movie )
collection = Collection.objects.create(movie=movie, **validated_data)
return collection
You need to overwrite the create method so when creating a Collection, you also create a movie.
However, I am not sure the foreign key is set in the right model in your model. (a movie belongs to many collection but not the other way around?) If that's not what you want, just reverse the logic for the serializer.
Edit:
Sending the following should work fine:
{ "uuid": "1001",
"title": "Action",
"description": "Action Movies",
"movie": { "title": "The Burkittsville 7",
"description": "The story of Rustin Parr.",
"genres": "Horror",
"uuid": "5e904"
}
}
The only problem as I mentionned earlier is in your model you defined the foreign key field in collection. So it expects one single movie instance and not a list, thus I took off the brackets you put around movie. Maybe you should consider setting the foreign key in the Movie model, or use a Many to many relationship.
#models.py
class Movie(models.Model):
# collection = models.ForeignKey(Collection, on_delete = models.CASCADE) #, related_name='reviews'
title = models.CharField(max_length=200)
description = models.CharField(max_length=200)
genres = models.CharField(max_length=200)
uuid = models.CharField(max_length=200)
def __str__(self):
return self.title
class Collection(models.Model):
title = models.CharField(max_length=200)
uuid = models.CharField(max_length=200, primary_key = True)
description = models.CharField(max_length=200)
movie = models.ManyToManyField(Movie, on_delete = models.CASCADE)
def __str__(self):
return self.title
serializers.py:
class MovieSerializer(serializers.ModelSerializer):
class Meta:
model = Movie
fields = '__all__'
class CollectionSerializer(serializers.ModelSerializer):
movie = MovieSerializer(read_only=True, many=True)
class Meta:
model = Collection
fields = '__all__'
hope this will give you better unserstand this will work for you
Looking for solution of this problem I encountered some similar threads, but referring to older versions of Django/DRF and thus not working in my case.
There are these two models:
class CsdModel(models.Model):
model_id = models.CharField("Item ID", max_length=8, primary_key=True)
name = models.CharField("Item Name", max_length=40)
active = models.BooleanField(default=True)
def __str__(self):
return self.model_id
class CsdListing(models.Model):
model_id = models.ForeignKey(CsdModel, on_delete=models.CASCADE, default=0, related_name='m_id')
name = models.ForeignKey(CsdModel, on_delete=models.CASCADE, default=0, related_name='m_name')
(...)
EDIT: Serializers are defined this way:
class CsdModelSerializer(serializers.ModelSerializer):
model_id = serializers.RegexField(regex='^\w{2}\d{3}$', allow_blank=False)
name = serializers.CharField(min_length=6, max_length=50, allow_blank=False)
class Meta:
model = CsdModel
fields = '__all__'
class CsdListingSerializer(serializers.ModelSerializer):
session_id = serializers.RegexField(regex='^s\d{2}$', allow_blank=False)
def validate_session_id(self, value):
(...)
class Meta:
model = CsdListing
fields = '__all__'
What I'd like to see, is model_id and name from CsdModel displayed inside a form created based on CsdListing model. But instead, the ID is duplicated:
How should I rebuild the model(s) to have both ID and name displayed in the form?
You should have only one foreign key. But the listing serializer should then reference the model as a nested serializer.
class CsdListing(models.Model):
model = models.ForeignKey(CsdModel, on_delete=models.CASCADE, default=0, related_name='listing')
class CsdListingSerializer(serializers.ModelSerializer):
model = CsdModelSerializer()
session_id = serializers.RegexField(regex='^s\d{2}$', allow_blank=False)
How can I set values on to a ManyToManyField which specifies an intermediary model?
In the models.py
class BookUser(models.Model):
email = models.EmailField()
class Book(models.Model):
author_id= models.CharField(max_length=255)
send_to = models.ManyToManyField(BookUser, through='BookUserRelationship')
book_id = models.AutoField(primary_key=True)
file_size = models.CharField(null=True)
class BookUserRelationship(models.Model):
book = models.ForeignKey(Book, on_delete=models.CASCADE)
user = models.ForeignKey(BookUser, on_delete=models.CASCADE)
shared_date = models.DateTimeField(auto_now_add=True,null=True,blank=True)
Tried to update in serializers.py
class BookSerializer(serializers.ModelSerializer):
send_to = BookUserSerializer(many=True, read_only=True)
class Meta():
model = Book
fields = ('book_id', 'author_id','file_size','send_to')
class BookUserSerializer(serializers.ModelSerializer):
model = BookUser
fields = ('email')
In the views.py for listing the books by passing the book_id as query params
class BookListView(generics.ListCreateAPIView):
serializer_class = serializers.BookSerializer
def get(self, request, *args, **kwargs):
user = self.request.user
book_id = self.request.query_params.get('book_id', None)
if book_id:
book = models.Book.objects.filter(book_id=book_id)
return Response(serializers.BookSerializer(book[0]).data)
You don't need to do anything at all. You have already set the relevant data in your for loop, by creating the BookUserRelationship instances. That is the many-to-many relationship; you should just remove the instance.send_to.set(emails) line.