In some cases, you may want your application to connect to a database that isn't hosted in Heroku. You can configure this connection by overriding the DATABASE_URL command.

To override this variable, you must provide the connection parameters:

postgres://[username]:[password]@[host]/[database name]

The Heroku client has the config:set command that allows you to define or override environment variables:

$ heroku config:set DATABASE_URL=' postgres://[username]:[password]@[host]/[database name]' -your-app-name
Setting config vars and restarting your-app-name... done, v11
DATABASE_URL: postgres://[username]:[password] @[host]:5432/[database name]