How to connect to multiple PostgreSQL schemas from Django?

Question

In my GeoDjango project I want to connect to a legacy PostgreSQL/PostGIS database. It contains the following schemas:

• data // contains all the geospatial data
• django // empty, created by me
• public // system tables such as spatial_ref_sys

I want the Django tables shown in the screenshot to go into the django schema. I do not want to pollute the public schema.

I want the "data" models to connect to the data schema. I already tried to generate models from the legacy tables but python manage.py inspectdb connects to the public schema.

---

In order to provide access to the different schemas I adapted the approach 2 of this article which preassigns individual search_path values to specific database users:

-- user accessing django schema...
CREATE ROLE django_user LOGIN PASSWORD 'secret';
ALTER ROLE django_user SET search_path TO django, public;

-- user accessing data schema...
CREATE ROLE data_user LOGIN PASSWORD 'secret';
ALTER ROLE data_user SET search_path TO data, public;

Then I configured the database connections as follows:

DATABASES = {

    'default': {
            'ENGINE': 'django.db.backends.postgresql_psycopg2',
            'NAME': 'multi_schema_db',
            'USER': 'django_user',
            'PASSWORD': 'secret',
    },

    'data': {
            'ENGINE': 'django.db.backends.postgresql_psycopg2',
            'NAME': 'multi_schema_db',
            'USER': 'data_user',
            'PASSWORD': 'secret',
    },
}

How can I actually configure that Django uses the django schema while "data" models connect to the data schema?

---

Readings

• How to use schemas in Django?
• How to specify schema name while running "syncdb" in django?
• Issue #6148 - Add generic support for database schemas

Answer 1

You have to leverage the search_path :

DATABASES = {

    'default': {
            'ENGINE': 'django.db.backends.postgresql_psycopg2',
            'OPTIONS' : {
                'options': '-c search_path=django,public'
            },
            'NAME': 'multi_schema_db',
            'USER': 'django_user',
            'PASSWORD': 'secret',
    },

    'data': {
            'ENGINE': 'django.db.backends.postgresql_psycopg2',
            'OPTIONS' : {
                'options': '-c search_path=data,public'
            },
            'NAME': 'multi_schema_db',
            'USER': 'data_user',
            'PASSWORD': 'secret',
    },
}

• Source: Accessing multiple Postgres schemas from Django

Answer 2

If you don't need to manage the tables through migrations, you could use escaped quotes for the db_table attribute of your model:

class SomeModel(models.Model):
    field1 = models.AutoField(primary_key=True)  
    class Meta():
        managed=False
        db_table=u'"schema\".\"table"'

Answer 3

We use Django Tenant Schemas with great success. It allows you to access different schemas by delineating different tenants as the owners of the schemas.

This will allow you to set the schema on a per call basis. If the schema needs to be set on a per url basis, you can do that in middleware.