自定义用户类和Postgresql模式的Django“关系不存在”错误

Question

I am getting a django.db.utils.ProgrammingError: relation "user" does not exist error when running createsuperuser on a Django project with a Postgresql database.

I wrote the following database router to indicate that the table user (which is based on a custom extension of the AbstractUser class) is in the schema users . Even so, Django cannot find it.

from myapp.models import Class1, Class2, Class3
from users.models import User
from django.contrib.admin.models import LogEntry
from django.contrib.contenttypes.models import ContentType
from django.contrib.sessions.models import Session

# Include here classes (i.e. tables) that belongs to the "myapp" schema
ROUTED_MODELS_MYAPP = [Class1, Class2, Class3]

# Include here classes (i.e. tables) that belongs to the "users" schema
ROUTED_MODELS_USERS = [User, LogEntry, ContentType, Session] #classes for custom user model, and django tables `django_admin_log`, `django_content_type`, `django_session` tables
# classes for the following table names still missing from list: `auth_group`, `auth_group_permissions`, `auth_permission`.

class MyDBRouter(object):
    """
    A router to place DB queries into correct schema depending on considered tables.
    Sources: 
        https://stackoverflow.com/a/51007441/3976696
        https://www.amvtek.com/blog/posts/2014/Jun/13/accessing-multiple-postgres-schemas-from-django/
    """
    def db_for_read(self, model, **hints):
        if model in ROUTED_MODELS_MYAPP:
            return 'myapp'
        elif model in ROUTED_MODELS_USERS:
            return 'users'
        return None

    def db_for_write(self, model, **hints):
        if model in ROUTED_MODELS_MYAPP:
            return 'myapp'
        elif model in ROUTED_MODELS_USERS:
            return 'users'        
        return None   

The router works for other tables unrelated to authentication, so I suspect this has to do with the other tables automatically created by Django when I migrated the User class for the first time ( auth_group , auth_group_permissions , auth_permission , django_admin_log , django_content_type , django_session ).

However, I'm not sure:

1. If the router is supposed to be written like I did (a sequence of if / elif ) --> is there a better way to write a router for more than one schema?
2. Which are the model names corresponding to the Django tables listed above. --> I was able to guess the three last class names ( django_admin_log , django_content_type , django_session ) by looking into django/contrib directories, but how am I supposed to find those for auth_group , auth_group_permissions , auth_permission ?

EDIT: based on the comment from @Kevin, I tried writing the routers based on app_label s rather than model names, as shown in the docs, making one router for each app involved. I also tried manually specifying the app_label in the Meta class of my User class (ie app_label = 'users' ).

However the original error ( django.db.utils.ProgrammingError: relation "user" does not exist ) persists when I enter a username in createsuperuser . How else am I supposed to handle this situation in the router?

#Route all models in admin application, cf. https://docs.djangoproject.com/en/2.1/topics/db/multi-db/
class AdminRouter:
    """
    A router to control all database operations on models in the admin application.
    """
    def db_for_read(self, model, **hints):
        """
        Attempts to read admin models go to users.
        """
        if model._meta.app_label == 'admin':
            return 'users'
        return None

    def db_for_write(self, model, **hints):
        """
        Attempts to write admin models go to users.
        """
        if model._meta.app_label == 'admin':
            return 'users'
        return None

    def allow_migrate(self, db, app_label, model_name=None, **hints):
        """
        Make sure the admin app only appears in the 'users' database.
        """
        if app_label == 'admin':
            return db == 'users'
        return None

class AuthRouter:
    """
    A router to control all database operations on models in the
    auth application.
    """
    <similar to previous router>

class ContentTypeRouter:
    """
    A router to control all database operations on models in the
    contenttype application.
    """
    <similar to previous router>

class SessionRouter:
    """
    A router to control all database operations on models in the
    sessionapplication.
    """
    <similar to previous router>

#Route all models in users application, cf. https://docs.djangoproject.com/en/2.1/topics/db/multi-db/
class UsersRouter:
    """
    A router to control all database operations on models in the users application.
    """
    def db_for_read(self, model, **hints):
        """
        Attempts to read user models go to users.
        """
        if model._meta.app_label == 'users':
            return 'users'
        return None

    def db_for_write(self, model, **hints):
        """
        Attempts to write user models go to users.
        """
        if model._meta.app_label == 'users':
            return 'users'
        return None

    def allow_migrate(self, db, app_label, model_name=None, **hints):
        """
        Make sure the user app only appears in the 'users' database.
        """
        if app_label == 'users':
            return db == 'users'
        return None

Then, I call them from settings.py in the following order:

DATABASE_ROUTERS = (
                    'urbio.dbrouters.AdminRouter',
                    'urbio.dbrouters.AuthRouter', 
                    'urbio.dbrouters.ContentTypeRouter', 
                    'urbio.dbrouters.SessionRouter', 
                    'urbio.dbrouters.UsersRouter',
                    )

Answer 1

The solution was to specify the --database flag and point to the correct schema when running the createsuperuser command:

python manage.py createsuperuser --database users

Also, following this answer , the database definition in settings.py is:

DATABASES = {

    'default': 
            {},

    'schema1': 
            {
            'ENGINE': 'django.db.backends.postgresql_psycopg2',
            'OPTIONS': {
                            'options': '-c search_path=schema1'
                        },
            'NAME': 'mydbname',
            'USER': 'myusername',
            'PASSWORD': '***',
            'HOST': 'my.host.address',
            'PORT': '5432',
            },

    'users': 
            {
            'ENGINE': 'django.db.backends.postgresql_psycopg2',
            'OPTIONS': {
                            'options': '-c search_path=users'
                        },
            'NAME': 'mydbname',
            'USER': 'myusername',
            'PASSWORD': '***',
            'HOST': 'my.host.address',
            'PORT': '5432',
            }

}