SQL> select name, status from v$datafile where status not in ('ONLINE', 'SYSTEM');2) take offline, recover datafile, bring it back online
SQL> alter datafile 'C:/ORACLEXE/ORADATA/XE/DATAFIEL_NAME.DBF' offline; SQL> recover datafile 'C:/ORACLEXE/ORADATA/XE/DATAFIEL_NAME.DBF'; SQL> alter datafile 'C:/ORACLEXE/ORADATA/XE/DATAFIEL_NAME.DBF' online;