django rest framework serializer method field how to - python

How do I handle this serializer method field? I feel that using initial_data is wrong, do i need to validate data when extracting it from the database? Do I need to use a serializer when extracting data from database?
class ListingSerializer(serializers.ModelSerializer):
rooms = serializers.SerializerMethodField()
# This one works as expected
def get_rooms(self, obj):
rooms = list(Room.objects.filter(listing__id=obj.id).values())
serializer = RoomSerializer(data=rooms, many=True)
return serializer.initial_data
# This one gives serializer errors
def get_rooms(self, obj):
rooms = list(Room.objects.filter(listing__id=obj.id).values())
serializer = RoomSerializer(data=rooms, many=True)
if serializer.is_valid():
return serializer.data
return serializer.errors
class Meta:
model = Listing
fields = "__all__"
class Listing(models.Model):
id = models.CharField(
primary_key=True, default=generate_uuid, editable=False, max_length=36
)
agent = models.ForeignKey(
"users.User", on_delete=models.CASCADE, blank=True, null=True
)
# property data
title = models.CharField(max_length=100, blank=False, null=False)
description = models.CharField(max_length=1000, blank=False, null=False)
floor = models.IntegerField(blank=False, null=False)
floor_count = models.IntegerField(blank=False, null=False)
price = models.DecimalField(max_digits=10, decimal_places=2, default=Decimal(0.00))
# address
street = models.CharField(max_length=60, blank=False, null=True)
house_no = models.CharField(max_length=10, blank=False, null=True)
door_no = models.CharField(max_length=10, blank=False, null=True)
city = models.CharField(max_length=20, blank=False, null=True)
country = models.CharField(max_length=20, blank=False, null=True)
postal_code = models.IntegerField(blank=False, null=True)
# property reports
tilstand_report = models.FileField(upload_to="reports", blank=False, null=True)
water_consumption_report = models.FileField(
upload_to="reports", blank=False, null=True
)
energy_level_report = models.FileField(upload_to="reports", blank=False, null=True)
property_tax_report = models.FileField(upload_to="reports", blank=False, null=True)
# metadata
is_active = models.BooleanField(default=True)
create_time = models.BigIntegerField(blank=True, null=True)
def save(self, *args, **kwargs):
self.create_time = int(datetime.now().timestamp() * 1000)
super().save(*args, **kwargs)
class Meta:
ordering = ["create_time"]

You can use the RoomSerializer as a sub serializer:
class ListingSerializer(serializers.ModelSerializer):
rooms = RoomSerializer(source='room_set', many=True)
class Meta:
model = Listing
fields = '__all__'
The source=… should specify the related_name=… of the ForeignKey in the Room model. If you did not specify a related_name=…, the default is modelname_set, so here room_set.

Related

Cannot assign "'Sample Category'": "Product.category" must be a "Category" instance

While creating new products I'm getting such kind of error. Can someone help me?
class Product(models.Model):
user = models.ForeignKey(User, on_delete=models.SET_NULL, null=True)
name_geo = models.CharField(max_length=200, null=True, blank=True)
image = models.ImageField(null=True, blank=True, default='/placeholder.png')
brand = models.CharField(max_length=200, null=True, blank=True)
category = models.ForeignKey(Category, null=False, default=0, on_delete=models.CASCADE)
price = models.DecimalField(max_digits=7, decimal_places=2, null=True, blank=True)
countInStock = models.IntegerField(null=True, blank=True, default=0)
createdAt = models.DateTimeField(auto_now_add=True)
_id = models.AutoField(primary_key=True, editable=False)
def __str__(self):
return self.name_geo
class Category(models.Model):
_id = models.AutoField(primary_key=True, editable=False)
name = models.CharField(max_length=200, null=True, blank=True)
createdAt = models.DateTimeField(auto_now_add=True)
def __str__(self):
return self.name
#api_view(['POST'])
def createProduct(request):
user = request.user
product = Product.objects.create(
user=user,
name_geo="Sample Name",
category="Sample Category",
price=0,
brand='Sample Brand',
countInStock=0,
)
serializer = ProductSerializer(product, many=False)
return Response(serializer.data)
Without separating category class in models.py everything works fine. I mean If i didn't use ForeignKey in Products class for category
It just has to be a Category Instance/Object
product = Product.objects.create(
user=user,
name_geo="Sample Name",
category=Category.objects.get_or_create(name="Sample Category"),
price=0,
brand='Sample Brand',
countInStock=0,
)
Notes:
You could just do a .get() or a .filter().first() if you don't want to create
If you use a form, you can get away with just the Category's PK/_id in the POST
this type of thing: f = form(request.POST) f.is_valid() f.save()
At the end that field will hold the PK/_id/Row# of the Category Obj

Django filterset and Django rest framework not working as expected

I have created a Django filter set to filter data, some fields are filtered with relationships.
When I never filter with the endpoint, it just returns all data instead of filtered data, what could be wrong here?
This is my endpoint filterer :
http://127.0.0.1:5000/api/v1/qb/questions/?paper=26149c3b-c3e3-416e-94c4-b7609b94182d&section=59bdfd06-02d4-4541-9478-bf495dafbee1&topic=df8c2152-389a-442f-a1ce-b56d04d39aa1&country=KE
Below is my sample :
from django_filters import rest_framework as filters
class QuestionFilter(filters.FilterSet):
topic = django_filters.UUIDFilter(label='topic',
field_name='topic__uuid',
lookup_expr='icontains')
sub_topic = django_filters.UUIDFilter(label='sub_topic',
field_name='topic__sub_topic__uuid',
lookup_expr='icontains')
paper = django_filters.UUIDFilter(label='paper',
field_name='paper__uuid',
lookup_expr='icontains')
section = django_filters.UUIDFilter(label='section',
field_name='section__uuid',
lookup_expr='icontains')
subject = django_filters.UUIDFilter(label='subject',
field_name="paper__subject__id",
lookup_expr='icontains'
)
year = django_filters.UUIDFilter(label='year',
field_name='paper__year__year',
lookup_expr="icontains")
country = django_filters.CharFilter(label='country',
field_name="paper__exam_body__country",
lookup_expr='icontains')
class Meta:
model = Question
fields = ['topic', 'section', 'paper', 'sub_topic', 'subject', 'year',
'country']
Then my view is like this :
class QuestionView(generics.ListCreateAPIView):
"""Question view."""
queryset = Question.objects.all()
serializer_class = serializers.QuestionSerializer
authentication_classes = (JWTAuthentication,)
filter_backends = (filters.DjangoFilterBackend,)
filterset_class = QuestionFilter
Then the models attached to the filter are as below :
class Question(SoftDeletionModel, TimeStampedModel, models.Model):
"""Questions for a particular paper model."""
uuid = models.UUIDField(unique=True, max_length=500,
default=uuid.uuid4,
editable=False,
db_index=True, blank=False, null=False)
mentor = models.ForeignKey(User, related_name='question_mentor', null=True,
on_delete=models.SET_NULL)
paper = models.ForeignKey(Paper, max_length=25, null=True,
blank=True, on_delete=models.CASCADE)
question = models.TextField(
_('Question'), null=False, blank=False)
section = models.ForeignKey(QuestionSection,
related_name='section_question',
null=True, on_delete=models.SET_NULL)
topic = models.ForeignKey(Course, related_name='topic_question',
null=True, on_delete=models.SET_NULL)
question_number = models.IntegerField(_('Question Number'), default=0,
blank=False, null=False)
image_question = models.ImageField(_('Image question'),
upload_to='image_question',
null=True, max_length=900)
answer_locked = models.BooleanField(_('Is Answer locked'), default=True)
status = models.CharField(max_length=50, choices=QUESTION_STATUSES,
default=ESSAY)
address_views = models.ManyToManyField(CustomIPAddress,
related_name='question_views',
default=None, blank=True)
bookmarks = models.ManyToManyField(User, related_name='qb_bookmarks',
default=None, blank=True)
def __str__(self):
return f'{self.question}'
Paper Model
class Paper(SoftDeletionModel, TimeStampedModel, models.Model):
"""Paper model."""
uuid = models.UUIDField(unique=True, max_length=500,
default=uuid.uuid4,
editable=False,
db_index=True, blank=False, null=False)
subject = models.ForeignKey(Subject, related_name='subject',
null=True, on_delete=models.SET_NULL)
mentor = models.ForeignKey(User, related_name='paper_mentor', null=True,
on_delete=models.SET_NULL)
year = models.DateField(_('Year'), blank=False, null=False)
grade_level = models.ForeignKey(ClassGrade, related_name='grade_paper',
null=True, on_delete=models.SET_NULL)
exam_body = models.ForeignKey(ExamBody, related_name='exam_body_paper',
null=True, on_delete=models.SET_NULL)
number_of_questions = models.IntegerField(_('No of questions'),
blank=False, null=False)
number_of_sections = models.IntegerField(_('No of sections'),
blank=False, null=False)
color_code = ColorField(format='hexa', default='#33AFFF', null=True)
class Meta:
ordering = ['created']
def __str__(self):
return f'{self.subject.name} ({self.year})'
QuestionSection Model :
class QuestionSection(SoftDeletionModel, TimeStampedModel, models.Model):
"""Question paper sections e.g Section A, B, C etc."""
uuid = models.UUIDField(unique=True, max_length=500,
default=uuid.uuid4,
editable=False,
db_index=True, blank=False, null=False)
section = models.CharField(
_('Question Section'), max_length=100, null=False, blank=False)
def __str__(self):
return f'{self.section}'
class Course(SoftDeletionModel, TimeStampedModel, models.Model):
"""
Topic model responsible for all topics.
"""
uuid = models.UUIDField(unique=True, max_length=500,
default=uuid.uuid4,
editable=False,
db_index=True, blank=False, null=False)
title = models.CharField(
_('Title'), max_length=100, null=False, blank=False)
overview = models.CharField(
_('Overview'), max_length=100, null=True, blank=True)
description = models.CharField(
_('Description'), max_length=200, null=False, blank=False
)
country = CountryField()
subject = models.ForeignKey(Subject, on_delete=models.CASCADE)
topic_cover = models.ImageField(
_('Topic Cover'), upload_to='courses_images',
null=True, blank=True, max_length=900)
grade_level = models.ForeignKey(
ClassGrade, max_length=25, null=True,
blank=True, on_delete=models.CASCADE)
user = models.ForeignKey(User, on_delete=models.CASCADE)
ranking = models.IntegerField(
_('Ranking of a Topic'), default=0, help_text=_('Ranking of a Topic')
)
def __str__(self):
return self.title
class Meta:
verbose_name_plural = "Topics"
ordering = ['ranking']

Django - Getting an object from an object

I'm trying to get the object "Book" from prommotion. Book is a ForeignKey in "prommotion", and I filtered all the prommotions that are active. I need to get the "Book" object from the Prommotion if its active and return it.
(And I know promotion is spelled wrong)
Views:
class Book_PrommotionViewSet(viewsets.ViewSet):
def list(self, request):
queryset = Prommotion.objects.filter(active=True)
serializer = PrommotionSerializer(queryset, many=True)
return Response(serializer.data, HTTP_200_OK)
Prommotion Model:
class Prommotion(models.Model):
id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
precent = models.DecimalField(decimal_places=2, max_digits=255, null=True, blank=True)
active = models.BooleanField(default=False)
date_from = models.DateField()
date_to = models.DateField()
book = models.ForeignKey(Book, on_delete=models.SET_NULL, null=True, blank=True)
country = models.ForeignKey(Country, on_delete=models.SET_NULL, null=True, blank=True)
created_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(auto_now=True)
class Meta:
verbose_name = 'Prommotion'
verbose_name_plural = 'Prommotions'
Book Model:
class Book(models.Model):
id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
title = models.CharField(max_length=255, null=True, blank=True)
author = models.ForeignKey(Author, on_delete=models.SET_NULL, null=True, blank=True)
price = models.DecimalField(decimal_places=2, max_digits=255)
published = models.DateField()
edition = models.CharField(max_length=255)
isbn_code = models.CharField(max_length=255)
pages = models.IntegerField(blank=True, null=True, default=0)
description = models.TextField(null=True, blank=True)
cover = models.CharField(max_length=30, choices=Cover.choices(), default=None, null=True, blank=True)
genre = models.CharField(max_length=30, choices=Genre.choices(), default=None, null=True, blank=True)
language = models.CharField(max_length=30, choices=Language.choices(), default=None, null=True, blank=True)
format = models.CharField(max_length=30, choices=Format.choices(), default=None, null=True, blank=True)
publisher = models.CharField(max_length=30, choices=Publisher.choices(), default=None, null=True, blank=True)
created_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(auto_now=True)
def __str__(self):
return self.title
class Meta:
verbose_name = 'Book'
verbose_name_plural = 'Books'
The first way to get all Books that are related to your active promotions is to extract the book ids from the queryset and pass it to a Book filter
active_promotions = Prommotion.objects.filter(active=True)
Book.objects.filter(id__in=active_promotions.values('book_id'))
Or simply filter books with active promotions by using the double underscore syntax to follow relationships
Book.objects.filter(prommotion__active=True).distinct()

Django: get the max count of a foreign key based on other foreign key

I have this Model:
class Complaint(models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, default=1)
date_created = models.DateTimeField(auto_now_add=True, null=True, blank=True)
name = models.CharField(max_length=255, unique=True)
definition = models.TextField(blank=False, default="")
is_violent = models.BooleanField(default=False)
is_active = models.BooleanField(default=True)
def __str__(self):
return self.name
class Meta:
ordering = ['name']
def get_absolute_url(self):
return reverse('complaint-details', kwargs={'pk': self.pk})
class Service(models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, default=1)
date_created = models.DateTimeField(auto_now_add=True, null=True, blank=True)
name = models.CharField(max_length=255, unique=True)
definition = models.TextField(blank=True, default="")
is_active = models.BooleanField(default=True)
def __str__(self):
return self.name
def get_absolute_url(self):
return reverse('service-details', kwargs={'pk': self.pk})
class Location(models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, default=1)
date_created = models.DateTimeField(auto_now_add=True, null=True, blank=True)
location_name = models.CharField(max_length=255, unique=True)
loc_lat = models.DecimalField(max_digits=9, decimal_places=6)
loc_long = models.DecimalField(max_digits=9, decimal_places=6)
pop = models.PositiveIntegerField(default=500)
is_AOR = models.BooleanField(default=False)
is_active = models.BooleanField(default=True)
def __str__(self):
return self.location_name
class Blotter(models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, default=1)
date_created = models.DateTimeField(auto_now_add=True, null=True, blank=True)#default=timezone.now().date()
date = models.DateField(blank=True)
time = models.TimeField(blank=True)
entry_number = models.CharField(max_length=255, unique=True,validators=[RegexValidator(r'^\d{1,255}$')])
complaints = models.ForeignKey(Complaint, on_delete=models.CASCADE, null=True, blank=True)
service = models.ForeignKey(Service, on_delete=models.CASCADE, null=True, blank=True)
information = models.TextField(blank=False, default="")
location = models.ForeignKey(Location, on_delete=models.CASCADE, null=True, blank=True)
is_active = models.BooleanField(default=True)
class Meta:
ordering = ("date_created",)
def __str__(self):
return (self.entry_number)
def get_absolute_url(self):
return reverse('details-blotter', kwargs={'pk': self.pk})
And I have this serializer:
class APILocationListSerializer(serializers.Serializer):
address = serializers.CharField()
latitude = serializers.DecimalField(max_digits=9, decimal_places=5)
longitude = serializers.DecimalField(max_digits=9, decimal_places=5)
population= serializers.IntegerField()
crime_count=serializers.IntegerField()
crime_rate=serializers.DecimalField(max_digits=4, decimal_places=3)
is_aor = serializers.BooleanField()
class Meta:
model = Blotter
fields= [
'address',
'latitude',
'longitude',
'population',
'crime_count',
'crime_rate'
'is_aor',
]
def to_representation(self, value):
context = {
value['address']:
{
'coordinates':[value['latitude'],value['longitude']],
'Population': value['population'],
'Crime-Count': value['crime_count'],
'Crime-Rate': value['crime_rate'],
'Area-Of-Responsibility': value['is_aor'],
}
}
return context
And ListApiView:
class APILocationList(generics.ListAPIView):
serializer_class = APILocationListSerializer
def get_queryset(self):
q=Blotter.objects.values('location__location_name').annotate(
address=F('location__location_name'),
latitude=F('location__loc_lat'),
longitude=F('location__loc_long'),
population=F('location__pop'),
crime_count=Count('complaints', filter=Q(complaints__is_active=True) and Q(complaints__isnull=False)),
crime_rate=(Cast(F('crime_count'), FloatField())/Cast(F('population'), FloatField()))*100000,
is_aor=F('location__is_AOR')
)
q1 = q.filter(location__is_AOR=True).order_by('address')
query_search = self.request.GET.get("q")
if query_search:
q1 = q.filter(Q(location__is_AOR=True) and Q(location__location_name__icontains=query_search)).order_by('address')
return q1
I'm new to django and DRF. I want to achieve a result like this in my API Not Achieved
but this is the result that i've achieved so far Achieved
As you can see in the picture, I want to count the crime trend (highest count of a crime and the crime itself) in every location.
My questions are:
Is this even achievable/possible to get these results using just one query?
If yes, how?
If no, is there any other way to achieve these kind of results?
Thank you in advance!

Django - conditional foreign key

I have the following 4 models in my program - User, Brand, Agency and Creator.
User is a superset of Brand, Agency and Creator.
A user can be a brand, agency or creator. They cannot take on more than one role. Their role is defined by the accountType property. If they are unset (i.e. 0) then no formal connection exists.
How do I express this in my model?
User model
class User(models.Model):
id = models.UUIDField(primary_key=True, default=uuid4, editable=False)
email = models.EmailField(max_length=255, null=True, default=None)
password = models.CharField(max_length=255, null=True, default=None)
ACCOUNT_CHOICE_UNSET = 0
ACCOUNT_CHOICE_BRAND = 1
ACCOUNT_CHOICE_CREATOR = 2
ACCOUNT_CHOICE_AGENCY = 3
ACCOUNT_CHOICES = (
(ACCOUNT_CHOICE_UNSET, 'Unset'),
(ACCOUNT_CHOICE_BRAND, 'Brand'),
(ACCOUNT_CHOICE_CREATOR, 'Creator'),
(ACCOUNT_CHOICE_AGENCY, 'Agency'),
)
account_id = models.ForeignKey(Brand)
account_type = models.IntegerField(choices=ACCOUNT_CHOICES, default=ACCOUNT_CHOICE_UNSET)
class Meta:
verbose_name_plural = "Users"
def __str__(self):
return "%s" % self.email
Brand model
class Brand(models.Model):
id = models.UUIDField(primary_key=True, default=uuid4, editable=False)
name = models.CharField(max_length=255, null=True, default=None)
brand = models.CharField(max_length=255, null=True, default=None)
email = models.EmailField(max_length=255, null=True, default=None)
phone = models.CharField(max_length=255, null=True, default=None)
website = models.CharField(max_length=255, null=True, default=None)
class Meta:
verbose_name_plural = "Brands"
def __str__(self):
return "%s" % self.brand
Creator model
class Creator(models.Model):
id = models.UUIDField(primary_key=True, default=uuid4, editable=False)
first_name = models.CharField(max_length=255, null=True, default=None)
last_name = models.CharField(max_length=255, null=True, default=None)
email = models.EmailField(max_length=255, null=True, default=None)
youtube_channel_username = models.CharField(max_length=255, null=True, default=None)
youtube_channel_url = models.CharField(max_length=255, null=True, default=None)
youtube_channel_title = models.CharField(max_length=255, null=True, default=None)
youtube_channel_description = models.CharField(max_length=255, null=True, default=None)
photo = models.CharField(max_length=255, null=True, default=None)
youtube_channel_start_date = models.CharField(max_length=255, null=True, default=None)
keywords = models.CharField(max_length=255, null=True, default=None)
no_of_subscribers = models.IntegerField(default=0)
no_of_videos = models.IntegerField(default=0)
no_of_views = models.IntegerField(default=0)
no_of_likes = models.IntegerField(default=0)
no_of_dislikes = models.IntegerField(default=0)
location = models.CharField(max_length=255, null=True, default=None)
avg_views = models.IntegerField(default=0)
GENDER_CHOICE_UNSET = 0
GENDER_CHOICE_MALE = 1
GENDER_CHOICE_FEMALE = 2
GENDER_CHOICES = (
(GENDER_CHOICE_UNSET, 'Unset'),
(GENDER_CHOICE_MALE, 'Male'),
(GENDER_CHOICE_FEMALE, 'Female'),
)
gender = models.IntegerField(choices=GENDER_CHOICES, default=GENDER_CHOICE_UNSET)
class Meta:
verbose_name_plural = "Creators"
def __str__(self):
return "%s %s" % (self.first_name,self.last_name)
Agency model
class Agency(models.Model):
id = models.UUIDField(primary_key=True, default=uuid4, editable=False)
name = models.CharField(max_length=255, null=True, default=None)
agency = models.CharField(max_length=255, null=True, default=None)
email = models.EmailField(max_length=255, null=True, default=None)
phone = models.CharField(max_length=255, null=True, default=None)
website = models.CharField(max_length=255, null=True, default=None)
class Meta:
verbose_name_plural = "Agencies"
def __str__(self):
return "%s" % self.agency
Update:
So I've whittled it down to this bit here in the model:
ACCOUNT_CHOICE_UNSET = 0
ACCOUNT_CHOICE_BRAND = 1
ACCOUNT_CHOICE_CREATOR = 2
ACCOUNT_CHOICE_AGENCY = 3
ACCOUNT_CHOICES = (
(ACCOUNT_CHOICE_UNSET, 'Unset'),
(ACCOUNT_CHOICE_BRAND, 'Brand'),
(ACCOUNT_CHOICE_CREATOR, 'Creator'),
(ACCOUNT_CHOICE_AGENCY, 'Agency'),
)
account_type = models.IntegerField(choices=ACCOUNT_CHOICES, default=ACCOUNT_CHOICE_UNSET)
limit = models.Q(app_label='api', model='Brand') | \
models.Q(app_label='api', model='Creator') | \
models.Q(app_label='api', model='Agency')
content_type = models.ForeignKey(ContentType, limit_choices_to=get_content_type_choices(), related_name='user_content_type')
content_object = GenericForeignKey('content_type', 'email')
If account_type = 1 then link to brand model
If account_type = 2 then link to creator model
If account_type = 3 then link to agency model
How do I accomplish this? Getting this error:
File "/Users/projects/adsoma-api/api/models.py", line 7, in <module>
class User(models.Model):
File "/Users/projects/adsoma-api/api/models.py", line 28, in User
content_type = models.ForeignKey(ContentType, limit_choices_to=get_content_type_choices(), related_name='user_content_type')
NameError: name 'get_content_type_choices' is not defined
Have you tried exploring Django's GenericForeignKey field?
class User(models.Model):
...
limit = models.Q(app_label='your_app_label', model='brand') |
models.Q(app_label='your_app_label', model='creator') |
models.Q(app_label='your_app_label', model='agency')
content_type = models.ForeignKey(ContentType, limit_choices_to=limit, related_name='user_content_type')
object_id = models.UUIDField()
content_object = GenericForeignKey('content_type', 'object_id')
You can access the User's brand/creator/agency by using the following notation:
User.objects.get(pk=1).content_object
This will be an instance of Brand/Creator/Agency as per the content_type.
https://docs.djangoproject.com/en/stable/ref/contrib/contenttypes/#django.contrib.contenttypes.fields.GenericForeignKey
Update based on your comment
Re 1: Using email:
class User(models.Model):
...
email = models.EmailField(max_length=255, unique=True)
limit = models.Q(app_label='your_app_label', model='brand') |
models.Q(app_label='your_app_label', model='creator') |
models.Q(app_label='your_app_label', model='agency')
content_type = models.ForeignKey(ContentType, limit_choices_to=get_content_type_choices, related_name='user_content_type')
content_object = GenericForeignKey('content_type', 'email')
Note: Email can not be a nullable field anywhere if you follow this approach! Also this approach seems hacky/wrong since the email field is now declared in multiple places; and the value can change if you re-assign the content objects. It is much cleaner to link the GenericForeignKey using the discrete UUIDField on each of the other three models
Re 2: Using account_type field:
ContentType is expected to be a reference to a Django Model; therefore it requires choices that are Models and not integers.
The function of limit_choices_to is to perform a filtering such that all possible models are not surfaced as potential GenericForeignKey
class ContentType(models.Model):
app_label = models.CharField(max_length=100)
model = models.CharField(_('python model class name'), max_length=100)
objects = ContentTypeManager()
However, limit_choices_to does accept callables; so you can write a helper method that translates your account_type to the correct Model
I am not clear about how this transaltion should work; so I leave that to you.
Here is how I solve it, override the save method check your condition
tested on Django 3.2
CUSTOMER = [
('customer', 'customer'),
('supplier', 'supplier'),
]
class Customer(models.Model):
name = models.CharField(max_length=256, null=False, blank=False)
user_type = models.CharField(max_length=32, choices=CUSTOMER)
class SupplierOrder(models.Model):
price = models.FloatField(default=0)
supplier = models.ForeignKey(Customer, related_name='supplier', on_delete=models.CASCADE)
def save(self, *args, **kwargs):
supplier = get_object_or_404(Customer, id=self.supplier.id)
if supplier.user_type != 'supplier':
raise ValueError('selected user must be supplier')
super().save(*args, **kwargs)

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