Oracle Database Discussions

DECLARE

db_role v$database.database_role%TYPE;

BEGIN

SELECT database_role INTO db_role from v$database;

IF db_role = 'PHYSICAL STANDBY' THEN

EXECUTE IMMEDIATE 'ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL';
END IF;

EXECUTE IMMEDIATE 'SHUTDOWN IMMEDIATE';

END;
/
the script is giving error for EXECUTE IMMEDIATE 'SHUTDOWN IMMEDIATE';

any suggestions?

Thanks