May be I it is very normal question but I am qurious to know if it is possible to create database role on Heroku Postgresql? i meane using this command:
CREATE ROLE "rolename";
Thank you.
UPDATE:
Yes. As of August 8, 2017 credential are available for Heroku Postgresql: https://devcenter.heroku.com/articles/heroku-postgresql-credentials
Heroku Postgres credentials are available only to production-class plans (Standard, Premium, Private, and Shield) on Postgres 9.6 and above. Hobby-tier plans include only the default credential, which cannot create other credentials or grant permissions.
Old answer:
No. You can not create or modify roles using a Heroku Postgres instance. From the Heroku documentation:
Heroku runs the SQL below to create a user and database for you.
You cannot create or modify databases and roles on Heroku Postgres.
The ability to create roles (for read-only access) is something that I've requested as a feature but it's not on the current roadmap as far as I know.