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The model is not displayed in the django admin panel

I don't have the advertisement module displayed in the django admin panel. Here is the model code
from django.db import models
class Advertisement(models.Model):
title = models.CharField(max_length=1000, db_index=True)
description = models.CharField(max_length=1000, default='', verbose_name='description')
creates_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(auto_now=True)
price = models.FloatField(default=0, verbose_name="price")
views_count = models.IntegerField(default=1, verbose_name="views count")
status = models.ForeignKey('AdvertisementStatus', default=None, null=True, on_delete=models.CASCADE,
related_name='advertisements')
def __str__(self):
return self.title
class Meta:
db_table = 'advertisements'
ordering = ['title']
class AdvertisementStatus(models.Model):
name = models.CharField(max_length=100)
admin.py /
from django.contrib import admin
from .models import Advertisement
admin.site.register(Advertisement)
I was just taking a free course from YouTube. This was not the case in my other projects. Here I registered the application got the name in INSTALLED_APPS. Then I performed the creation of migrations and the migrations themselves. Then I tried to use the solution to the problem here , nothing helped. I didn't find a solution in Google search either.
127.0.0.1:8000/admin/
console

admins.py
The name of the file is admin.py not admins.py. Yes, that is a bit confusing since most module names in Django are plural. The rationale is probably that you define a (single) admin for the models defined.
Alternatively, you can probably force Django to import this with the AppConfig:
# app_name/apps.py
from django.apps import AppConfig
class AppConfig(AppConfig):
def ready(self):
# if admin definitions are not defined in admin.py
import app_name.admins # noqa

I'm using Geodjango to implement a geolocation system for my system but it keeps raising a value error

'''from django.contrib.gis.db import models
class Store(models.Model):
name = models.CharField(max_length = 100)
coords= models.PointField()
store_id = models.IntegerField()'''

Django and Geodjango models must be imported separately.
One solution is to import django models normally and alias the spatial models import.
from django.db import models
from django.contrib.gis.db import models as sp_models
class Store(models.Model):
name = models.CharField(max_length=100)
coords = sp_models.PointField()
store_id = models.IntegerField()

how to avoid circular django model import?

I have these models below
# user profile models file
from ad.models import FavoriteAd
class UserProfile(models.Model):
def get_user_favorite_ad(self):
return FavoriteAd.objects.filter(fav_user=self)
# ad models file
from user_profile.models import UserProfile
class FavoriteAd(models.Model):
fav_user = models.ForeignKey(UserProfile, blank=False, on_delete=models.CASCADE)
I have tried using these but it give me the NameError UserProfile not found
# ad models files
class FavoriteAd(models.Model):
fav_user = models.ForeignKey('user_profile.UserProfile', blank=False, on_delete=models.CASCADE)
Also tried these as well still got error that model are not ready
# ad models files
from django.apps import apps
UserProfile = apps.get_model('user_profile', 'UserProfile')
class FavoriteAd(models.Model):
fav_user = models.ForeignKey(UserProfile, blank=False, on_delete=models.CASCADE)

You are using FavoriteAd inside get_user_favorite_ad method of
UserProfile model
Thats the reason you are unable to import it in FavoriteAd and this is causing circular import.
For fetching favorite ads of that user, Use favoritead_set to get related objects
# remove that import as well
# from ad.models import FavoriteAd
class UserProfile(models.Model):
def get_user_favorite_ad(self):
return self.favoritead_set.all()

Can't import serializer from other serializer in django rest-framework?

Problem
I have 2 models, leads and notes. I want a lead to be able to have 1 or more notes. I have used a generic foreign key because I want to plan for the future and a note could be assigned to say a person or a meeting for example.
Following the instructions for django rest framework and Rest Framework Generic Relations I am trying to import one serializer from the other to make a reverse relation possible.
Error
I can't import the serializers in both files(call one serializer from the other) because I get:
File "/Users/james/Documents/UtilityCRM-Server/crm/leads/urls.py", line 2, in <module>
from leads import views
File "/Users/james/Documents/UtilityCRM-Server/crm/leads/views.py", line 11, in <module>
from leads.serializers import LeadSerializer
File "/Users/james/Documents/UtilityCRM-Server/crm/leads/serializers.py", line 4, in <module>
from notes.serializers import NoteSerializer
File "/Users/james/Documents/UtilityCRM-Server/crm/notes/serializers.py", line 6, in <module>
from leads.serializers import LeadSerializer
ImportError: cannot import name LeadSerializer
Its weird because if I open the django shell and run the following it lets me import them all:
from leads.serializers import LeadSerializer
from notes.serializers import NotesSerializer
from callbacks.serializers import CallbackSerializer
Any help would be greatly appreciated!
Code
This is my installed app section of my settings file:
INSTALLED_APPS = [
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
# 3rd Party Apps
'rest_framework',
'generic_relations',
# My Apps
'leads.apps.LeadsConfig',
'callbacks.apps.CallbacksConfig',
'notes.apps.NotesConfig',
]
notes/models.py
from __future__ import unicode_literals
from django.db import models
from django.utils import timezone
from django.contrib.contenttypes.fields import GenericForeignKey
from django.contrib.contenttypes.models import ContentType
class Note(models.Model):
author = models.ForeignKey('auth.User')
title = models.CharField(max_length=100)
text = models.TextField()
created_date = models.DateTimeField(default=timezone.now)
# Relations
content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
object_id = models.PositiveIntegerField()
note_object = GenericForeignKey('content_type', 'object_id')
def __str__(self):
return self.title
leads/models.py
from __future__ import unicode_literals
from django.db import models
from django.contrib.contenttypes.fields import GenericRelation
from django.utils import timezone
from notes.models import Note
from callbacks.models import Callback
GAS = 'G'
ELECTRICITY = 'E'
LEAD_TYPE_CHOICES = (
(GAS, 'Gas'),
(ELECTRICITY, 'Electricity'),
)
# Create your models here.
class Lead(models.Model):
author = models.ForeignKey('auth.User')
type = models.CharField(
max_length=1,
choices=LEAD_TYPE_CHOICES,
default=GAS,
)
business_registration_number = models.IntegerField(max_length=20)
business_name = models.CharField(max_length=50)
mpan = models.IntegerField(max_length=21)
supplier = models.CharField(max_length=45)
contract_length = models.IntegerField(max_length=2)
contract_start_date = models.DateField()
contract_end_date = models.DateField()
address_line_1 = models.CharField(max_length=45)
address_line_2 = models.CharField(max_length=45)
address_line_3 = models.CharField(max_length=45)
address_city = models.CharField(max_length=45)
address_county = models.CharField(max_length=45)
address_postcode = models.CharField(max_length=10)
contact_title = models.CharField(max_length=45)
contact_first_name = models.CharField(max_length=45)
contact_middle_name = models.CharField(max_length=45)
contact_last_name = models.CharField(max_length=45)
contact_telephone = models.IntegerField(max_length=11)
contact_email = models.EmailField(max_length=60)
created_date = models.DateTimeField(default=timezone.now)
# Relations
assigned_to = models.ForeignKey('auth.User', related_name='+')
#from_batch = models.ForeignKey('data_batch.DataBatch', related_name='+')
#callbacks = GenericRelation(Callback)
notes = GenericRelation(Note)
class Meta:
ordering = ('contract_end_date', 'business_name',)
def __str__(self):
return self.business_name
I have 2 serializers:
leads/serializers.py
from rest_framework import serializers
from leads.models import Lead, LEAD_TYPE_CHOICES
from notes.serializers import NoteSerializer
class LeadSerializer(serializers.ModelSerializer):
notes = NoteSerializer(many=True, read_only=True)
class Meta:
model = Lead
fields = (
'id',
'business_name',
'business_registration_number',
'supplier',
'contract_length',
'contract_start_date',
'notes'
)
notes/serializers.py
from generic_relations.relations import GenericRelatedField
from rest_framework import serializers
from notes.models import Note
from leads.models import Lead
from leads.serializers import LeadSerializer
from callbacks.models import Callback
from callbacks.serializers import CallbackSerializer
class NoteSerializer(serializers.ModelSerializer):
"""
A `Note` serializer with a `GenericRelatedField` mapping all possible
models to their respective serializers.
"""
note_object = GenericRelatedField({
Lead: LeadSerializer(),
Callback: CallbackSerializer()
})
class Meta:
model = Note
fields = (
'id',
'author',
'title',
'text',
'created_date',
'note_object',
)

As I have mentioned previously in a comment, I believe this happens due to circular (cyclic) imports in Python.
This happens particularly when you are declaring related fields in models, and some models have not been instanced yet.
In this case, when you execute your program, it tries to import LeadSerializer, that requires importing NoteSerializer, that requires importing LeadSerializer, that requires importing NoteSerializer... see where this is going?
Your stacktrace says it all:
from leads.serializers import LeadSerializer
from notes.serializers import NoteSerializer
from leads.serializers import LeadSerializer
Generating ImportError: cannot import name LeadSerializer
What I have done to solve this was declaring all the serializers in a single file. Therefore, you have two options:
Move LeadSerializer to notes/serializers.py
Move NoteSerializer to leads/serializers.py
It is not the most elegant way to solve this, but it has done its trick.
The section below provides no further explanation on how to solve this problem, but an observation regarding this issue.
Perhaps Django & DRF could futurely provide methods to avoid this, such as declaring the serializers as
note_object = GenericRelatedField({
Lead: 'leads.serializers'.LeadSerializer,
Callback: CallbackSerializer()
})
or
notes = 'notes.serializers'.NoteSerializer(many=True, read_only=True)

Faced with this and made this thing:
notes = serializers.SerializerMethodField()
def get_notes(self, obj):
from leads.serializers import LeadSerializer
return LeadSerializer(<your_queryset>, many=True/False, read_only=True/False).data

There is an idea to tackle this before I have also got this same error here I will explain to you how I resolve this.
Put your apps inside the project directory
project
-project
-appname1
-models.py
-serilizer.py
-appname2
-models.py
-serilizer.py
-settings.py
in settings.py
INSTALLED_APPS = ['project.appname1', 'project.appname2']
then try to import appname1 serializers into appname2
like this
from project.appname1.serializers import( ArtistSerializer, ArtisTokenSerilizer, ProfessionSerilizer, FollowersSerializer,
FollowingSerializer, ChatMessageSerializer, SendMessageSerializer, ConversationMessageSerializer,
ProjectTypeSerializer)

Model has either not been installed or is abstract

When I try to migrate my code I get this error.
Here are my code and classes:
from django.db import models
from core.models import Event
class TicketType(models.Model):
name = models.CharField(max_length=45)
price = models.DecimalField(max_length=2, decimal_places=2, max_digits=2)
type = models.CharField(max_length=45)
amount = models.IntegerField()
event = models.ForeignKey(Event)
class Meta:
app_label = "core"
import datetime
from django.core.serializers import json
from django.db import models
from core.models import User
class Event(models.Model):
page_attribute = models.TextField()
name = models.TextField(max_length=128 , default="New Event")
description = models.TextField(default="")
type = models.TextField(max_length=16)
age_limit = models.IntegerField(default=0)
end_date = models.DateTimeField(default=datetime.datetime.now())
start_date = models.DateTimeField(default=datetime.datetime.now())
is_active = models.BooleanField(default=False)
user = models.ForeignKey(User)
ticket_type=models.ForeignKey('core.models.ticket_type.TicketType')
class Meta:
app_label = "core"
Here is the error I get:
CommandError: One or more models did not validate:
core.event: 'ticket_type' has a relation with model core.models.ticket_type.TicketType,
which has either not been installed or is abstract.

You're unnecessarily confusing yourself by having these in separate files within the same app.
But your issue is caused by the way you're referenced the target model. You don't use the full module path to the model: you just use 'app_name.ModelName'. So in your case it should be:
ticket_type=models.ForeignKey('core.TicketType')

Another issue can be when using multiple models in separate files missing statement like:
class Meta:
app_label = 'core_backend'

You can also get this error if there a bug in your models file that prevents it from loading properly. For example, in models.py
from third_party_module_i_havent_installed import some_method

I hit this error when I didn't put a third-party app in my INSTALLED_APPS setting yet.