how can I fix this error in Django admin and veiws files?

Question

I have a problem with a custom User model in my Account app and I just put.

AUTH_USER_MODEL = 'Account.User' in my setting.py.

The problem I'm having is that when I go to the admin panel and click on a user in the Users list, I receive an error (this error is not only for the User model but also for all other models in the admin panel; I can't delete or update them).

IntegrityError at /admin/Account/user/1/delete/

FOREIGN KEY constraint failed

IntegrityError at /admin/Account/user/1/change/

FOREIGN KEY constraint failed

---

Also, if I try to register a user using my register view, I get this error, which I return as a response if the user already exists in the Users list.

{
    "error": "Username has been already used."
}

The register view class code for checking the email and username:

if User.objects.filter(email=email).exists():
                return Response(data={"error": "Email has been already used."},
                                status=status.HTTP_400_BAD_REQUEST)

if User.objects.filter(username=username).exists():
                return Response(data={"error": "Username has been already used."},
                                status=status.HTTP_400_BAD_REQUEST)

My User Model:

from django.db import models
from django.contrib.auth.models import AbstractUser, Group, Permission


class User(AbstractUser):
    id = models.AutoField(primary_key=True)
    email = models.EmailField(unique=True)
    full_name = models.CharField(max_length=255, default="")
    simple_description = models.CharField(max_length=255, default="tourist")
    biography = models.TextField(null=True, blank=True, default="")
    profile_picture = models.ImageField(null=True, blank=True)
    
    groups = models.ManyToManyField(Group, blank=True, related_name='account_users')
    user_permissions = models.ManyToManyField(Permission, blank=True, related_name='account_users')

    def __str__(self):
        return self.username

My admin codes:

from django.contrib import admin
from Destination.models import Destination, DestinationImages
from Account.models import User, Profile


class DestinationImagesInline(admin.TabularInline):
    model = DestinationImages


@admin.register(Destination)
class DestinationAdmin(admin.ModelAdmin):

    inlines = [DestinationImagesInline]

    list_display = ["id", "name", "category", "rating", "author"]
    list_filter = ["category", "rating"]
    search_fields = ["name", "author__username"]
    sortable_by = ["id"]

    fieldsets = (
        ("General Info", {
            "fields": ("author", "name", "rating")
        }),

        ("Details", {
            "fields": ("category", "description")
        }),

        ("Location", {
            "classes": ("collapse",),
            "fields": ("location",)
        }),
    )


class ProfileInline(admin.StackedInline):
    model = Profile


@admin.register(User)
class UserAdmin(admin.ModelAdmin):
    inlines = [ProfileInline]

    list_display = ['username', 'email', 'full_name', 'id', 'is_active', 'is_staff', 'is_superuser']
    search_fields = ['username', 'email', 'full_name']
    list_filter = ['is_staff', 'is_superuser', 'is_active']

    fieldsets = (
        (None, {
            'fields': ('username', 'email', 'password')
        }),

        ('Personal Info', {
            'fields': ('full_name', 'simple_description', 'biography', 'profile_picture')
        }),

        ('Permissions', {
            'fields': ('is_active', 'is_staff', 'is_superuser', 'groups', 'user_permissions')
        }),

        ('Important dates', {
            'fields': ('last_login', 'date_joined')
        }),
    )

    readonly_fields = ('last_login', 'date_joined')

I also checked that I used on_delete=models.CASCADE in every field in other models that have a Foreign Key with a model

Answer 1

it seems you’ve created database tables with Django’s built-in User model . than you overrided the default user model with AUTH_USER_MODEL . but the model referenced by AUTH_USER_MODEL must be created in the first migration of its app (usually called 0001_initial); otherwise, you’ll have dependency issues.

Solution :

Delete/Drop the whole database and redo the migrations :

1- In the migrations folders of the USER app , delete all files (e.g. 001_initial.py) and pycache folder, except for init.py

2- Run python manage.py makemigrations Then run python manage.py migrate