通过logminer挖掘日志文件、有助于恢复数据库文件、
是因为日志文件中记录了数据块的信息。
----查看日志的位置和状态
SQL> col member for a45
SQL> select group#,status from v$log;

    GROUP# STATUS
---------- ----------------
         1 CURRENT
         2 INACTIVE
         3 INACTIVE

SQL> select group#,member from v$logfile;

    GROUP# MEMBER
---------- ---------------------------------------------
         3 /u01/app/oracle/oradata/ORA11GR2/redo03.log
         2 /u01/app/oracle/oradata/ORA11GR2/redo02.log
         1 /u01/app/oracle/oradata/ORA11GR2/redo01.log

SQL>
----修改数据库启动补充日志
SQL> ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (PRIMARY KEY, UNIQUE INDEX) COLUMNS;

Database altered.
----进行数据更改
SQL> insert into t values ('q');

1 row created.

SQL> commit;

Commit complete.

SQL>
----添加日志文件
SQL> exec dbms_logmnr.add_logfile('/u01/app/oracle/oradata/ORA11GR2/redo01.log',dbms_logmnr.addfile);

PL/SQL procedure successfully completed.
----启动挖掘日志
SQL> exec sys.dbms_logmnr.start_logmnr(options=>sys.dbms_logmnr.dict_from_online_catalog);

PL/SQL procedure successfully completed.
----将数据写入表中
SQL> create table d as select * from v$logmnr_contents;

Table created.

SQL>

----结束logmnr
SQL>exec sys.dbms_logmnr.end_logmnr();

PL/SQL procedure successfully completed.

SQL>