Something in my head is not how it does not fit, how do I refer to an already existing one(that is, a second or separate database) from under Django.Lets say there is a main site database(which Django created automatically) db.sqlite3.sqlite3? it is spelled out in settings as follows:
DATABASES={
    'default': {
        'ENGINE':'django.db.backends.sqlite3',
        'NAME': os.path.join(BASE_DIR,'db.sqlite3'),
    },

But I want to extract some data from the second database called: BDtest.db
For this, I registered it in settings:
DATABASES={
    'default': {
        'ENGINE':'django.db.backends.sqlite3',
        'NAME': os.path.join(BASE_DIR,'db.sqlite3'),
    },
    'CSDNbd': {
        'ENGINE':'django.db.backends.sqlite3',
        'NAME': os.path.join(BASE_DIR,'BDtest'),
    }
}

How do I access data from an existing table? Especially if it is not the default...
After all, when I create a model in models.py, then immediately and a new table is created, especially since a simple reference implies a reference to the default database, or I do not understand correctly?