Determining if an Oracle Database Is Primary or Standby

#How to find if database is Primary or Standby in Oracle SQL> select name,open_mode,controlfile_type,database_role from v$database; NAME      OPEN_MODE            CONTROL DATABASE_ROLE --------- -------------------- ------- ---------------- PLUGDB    READ WRITE           CURRENT PRIMARY SQL> select name,open_mode,database_role from v$database; NAME      OPEN_MODE            DATABASE_ROLE --------- -------------------- ---------------- PR        MOUNTED              PHYSICAL STANDBY