开启归档

SQL> archive log list
Database log mode              No Archive Mode
Automatic archival             Disabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     315
Current log sequence           317

SQL> select name,ARCHIVE_CHANGE#,log_mode from v$database;

NAME      ARCHIVE_CHANGE# LOG_MODE
--------- --------------- ------------
ORCL              4876453 NOARCHIVELOG

SQL> alter database mount;

Database altered.

SQL> alter database archivelog;

Database altered.

SQL> alter system switch logfile;

System altered.