Django Relational managers - python

I was trying to delete my Apllication model:
class Application(models.Model):
app_type = models.ForeignKey(ApplicationCategory, on_delete=models.CASCADE, related_name='applications')
fio = models.CharField(max_length=40)
phone_number = models.CharField(max_length=90)
organisation_name = models.CharField(max_length=100, null=True, blank=True)
aid_amount = models.PositiveIntegerField()
pay_type = models.CharField(max_length=1, choices=PAY_CHOICES, default=PAY_CHOICES[0][0])
status = models.ForeignKey(AppStatus, on_delete=models.CASCADE, related_name='applications', null=True, blank=True)
created = models.DateTimeField(auto_now_add=True)
benefactor = models.ForeignKey(Benefactor, on_delete=models.CASCADE, related_name='applications', null=True)
def __str__(self):
return f"id={self.id} li {self.fio} ning mablag\'i!"
and this was my Benefactor model:
class Benefactor(models.Model):
fio = models.CharField(max_length=255)
phone_number = models.CharField(max_length=9)
image = models.ImageField(upload_to='media/')
sponsory_money = models.IntegerField()
organisation_name = models.CharField(max_length=55, null=True, blank=True)
def __str__(self):
return f"{self.fio}"
But I got the below message on superAdmin Panel:
TypeError at /admin/api/benefactor/
create_reverse_many_to_one_manager.\<locals\>.RelatedManager.__call__() missing 1 required keyword-only argument: 'manager'
I would expect delete smoothly!!

Your Benefactor model has several ForeignKey relationships that share the related_name. Give each a unique name and rerun your migrations.

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 - 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()

automatically add a new models to admin page

i have a calculator app, inside it i have a Transaction , Family_group , Family_member models see pic below.
i want everytime i try to make a new Transaction there will be a default 1 Family_group and Family_member added automatically, without me starting one each time. is there any way to do it ?
models.py
class Transaction(models.Model):
income_period_choices = (('Weekly', 'Weekly'), ('Fortnightly',
'Fortnightly'))
chp_reference = models.CharField(max_length=50, unique=True)
rent_effective_date = models.DateField(null=True, blank=True)
income_period = models.CharField(max_length=11,
choices=income_period_choices,
null=True,
blank=True, default='Weekly')
property_market_rent = models.DecimalField(help_text='Weekly',
max_digits=7,
decimal_places=2,
null=True,
blank=True)
class FamilyGroup(models.Model):
name_choices = (('FG_1', 'FG_1'), ('FG_2',
'FG_2'), ('FG_3', 'FG_3'), ('FG_4',
'FG_4'), ('FG_5', 'FG_5'))
name = models.CharField(max_length=10, choices=name_choices)
transaction = models.ForeignKey(Transaction, on_delete=models.CASCADE)
family_type = models.ForeignKey(FamilySituation,
on_delete=models.PROTECT,
null=True,
blank=True)
class FamilyMember(models.Model):
transaction = models.ForeignKey(Transaction, on_delete=models.CASCADE)
family_group = models.ForeignKey(FamilyGroup,
on_delete=models.CASCADE,
null=True,
blank=True)
name = models.CharField(max_length=100, null=True, blank=True)
date_of_birth = models.DateField(null=True, blank=True)
relationship = models.ForeignKey(Relationship, on_delete=models.PROTECT)
Without seeing your code, it's hard to help, but this might get you started:
You can override the save method on the Transaction model like so:
class Transaction(models.Model):
...
def save(self, *args, **kwargs):
# add / create family group if it is missing:
if not self.family_group:
self.family_group = <the Family_group instance>
# add / create family member if it is missing:
if not self.family_group.family_member_set.all()
self.family_group.add([<the Family_member instance>])
self.family_group.save()
return super(Transaction, self).save(*args, **kwargs)

django - Runpython function to turn charfield into foreignkey

I've been strugglin to relate a csv imported data model with a spatial data model based on a CharField.
I've created both models and now im trying to transfer the data from one field to a new one to be the ForeignKey field. I made a Runpython funtion to apply on the migration but it goives the an error:
ValueError: Cannot assign "'921-5'":
"D2015ccccccc.rol_fk" must be a "D_Base_Roles" instance.
Here are the models:
class D_Base_Roles(models.Model):
predio = models.CharField(max_length=254)
dest = models.CharField(max_length=254)
dir = models.CharField(max_length=254)
rol = models.CharField(primary_key=True, max_length=254)
vlr_tot = models.FloatField()
ub_x2 = models.FloatField()
ub_y2 = models.FloatField()
instrum = models.CharField(max_length=254)
codzona = models.CharField(max_length=254)
nomzona = models.CharField(max_length=254)
geom = models.MultiPointField(srid=32719)
def __str__(self):
return str(self.rol)
class Meta():
verbose_name_plural = "Roles"
class D2015ccccccc(models.Model):
id = models.CharField(primary_key=True, max_length=80)
nombre_archivo = models.CharField(max_length=180, blank=True, null=True)
derechos = models.CharField(max_length=120, blank=True, null=True)
dir_calle = models.CharField(max_length=120, blank=True, null=True)
dir_numero = models.CharField(max_length=120, blank=True, null=True)
fecha_certificado = models.CharField(max_length=50, blank=True, null=True)
numero_certificado = models.CharField(max_length=50, blank=True, null=True)
numero_solicitud = models.CharField(max_length=50, blank=True, null=True)
rol_sii = models.CharField(max_length=50, blank=True, null=True)
zona_prc = models.CharField(max_length=120, blank=True, null=True)
##NEW EMPTY FOREIGNKEY FIELD
rol_fk = models.ForeignKey(D_Base_Roles, on_delete=models.CASCADE, blank=True, null=True)
def __str__(self):
return str(self.numero_certificado)
class Meta:
managed = True
#db_table = 'domperm2015cip'
verbose_name_plural = "2015 Certificados Informaciones Previas"
ordering = ['numero_certificado']
The Runpython function:
def pop_rol(apps, schema_editor):
roles = apps.get_model('b_dom_edificacion', 'D2015ccccccc')
for r in roles.objects.all():
rol = roles
r.rol_fk = r.rol_sii
r.save()
D_Base_Roles.rol values are all unique, and 921-5 is one of those values.
What am I missing?
You probably need to assign an object, not a string. Change the line
r.rol_fk = r.rol_sii
to
r.rol_fk = D_Base_Roles.objects.get(rol=r.rol_sii)
Maybe adjust to whatever the correct field for looking up D_Base_Roles instances is.
Note: this will make a database query for every iteration of the for-loop

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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