20160215150949_add_sequence_for_versions_dynamically.rb

      CREATE FUNCTION create_tr_sequence_for_ca() RETURNS trigger
        LANGUAGE plpgsql
        AS $$
          BEGIN
            execute format('create sequence tr_seq_%s', NEW.id);
            RETURN NEW;
          END
        $$;

      CREATE TRIGGER create_tr_sequence_for_ca AFTER INSERT ON client_accounts FOR EACH ROW EXECUTE PROCEDURE create_tr_sequence_for_ca();

      CREATE FUNCTION next_version_for_tr() RETURNS trigger
        LANGUAGE plpgsql
        AS $$
          BEGIN
            NEW.version := nextval('tr_seq_' || NEW.client_account_id);
            RETURN NEW;
          END
        $$;

      CREATE TRIGGER next_version_for_tr BEFORE INSERT ON translation_requests FOR EACH ROW EXECUTE PROCEDURE next_version_for_tr();