CODEWITHSUNDEEP
pythondjangodjango-database
Pavel Shlepnev
Pavel Shlepnev

Reputation: 165

Routing and middleware for multiple databases in Django

I have a problem correctly setting my middleware and routers to support multiple databases, one for each language (I decided to keep them separate).

I tried to use this solution, but for now I didn't get much use of it.

In my settings.py databases and middleware are defined as follows:

DATABASES = {
    'default': {},
    'ru': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': 'db_ru.sqlite3',
    },
    'en': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': 'db_en.sqlite3',
    }
}

DATABASE_ROUTERS = ['me.middleware.database_routing.DatabaseRouter']

MIDDLEWARE = [
    'me.middleware.database_routing.RouterMiddleware',
    'django.middleware.security.SecurityMiddleware',
    'whitenoise.middleware.WhiteNoiseMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.locale.LocaleMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

database_routing.py used in 'me.middleware.database_routing' fully corresponds to this middleware.

I get an error when starting the server: RouterMiddleware() takes no arguments. I believe there's some shortcoming concerning the middleware code. Also I cannot migrate to my databases, I get ValueError: Cannot assign "<ContentType: ContentType object (1)>": the current database router prevents this relation.

Maybe, there is some other solution?

Upvotes: 4

Views: 2203

Answers (1)

Preena John Prakash
Preena John Prakash

Reputation: 41

if your database_routing.py contains the below section, it is stopping the relationships to create in Django.

So, try commenting on the commented lines and return only true. This worked for me!

def allow_relation(self, obj1, obj2, **hints):
        """
        Do not allow relations involving the remote database
        """
        # print("in allow relation")
        # if obj1._meta.app_label == Organization or \
        #    obj2._meta.app_label == Organization:
        #    return True
        # return None
        return True

Upvotes: 1

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