Django Database Routers Adding a Database Routing file
Example
To use multiple databases in Django, just specify each one in settings.py:
DATABASES = {
'default': {
'NAME': 'app_data',
'ENGINE': 'django.db.backends.postgresql',
'USER': 'django_db_user',
'PASSWORD': os.environ['LOCAL_DB_PASSWORD']
},
'users': {
'NAME': 'remote_data',
'ENGINE': 'django.db.backends.mysql',
'HOST': 'remote.host.db',
'USER': 'remote_user',
'PASSWORD': os.environ['REMOTE_DB_PASSWORD']
}
}
Use a dbrouters.py file to specify which models should operate on which databases for each class of database operation, e.g. for remote data stored in remote_data, you might want the following:
class DbRouter(object):
"""
A router to control all database operations on models in the
auth application.
"""
def db_for_read(self, model, **hints):
"""
Attempts to read remote models go to remote database.
"""
if model._meta.app_label == 'remote':
return 'remote_data'
return 'app_data'
def db_for_write(self, model, **hints):
"""
Attempts to write remote models go to the remote database.
"""
if model._meta.app_label == 'remote':
return 'remote_data'
return 'app_data'
def allow_relation(self, obj1, obj2, **hints):
"""
Do not allow relations involving the remote database
"""
if obj1._meta.app_label == 'remote' or \
obj2._meta.app_label == 'remote':
return False
return None
def allow_migrate(self, db, app_label, model_name=None, **hints):
"""
Do not allow migrations on the remote database
"""
if model._meta.app_label == 'remote':
return False
return True
Finally, add your dbrouter.py to settings.py:
DATABASE_ROUTERS = ['path.to.DbRouter', ]
