關於SYSTEM表空間的表刪除後不會進入回收站的疑惑

咱們知道Oracle有一個回收站的功能，若是刪除表的時候不使用purge選項，則會進入到回收站，能夠使用Flashback閃回刪除。具體以下： SQL> select * from v$version; BANNER Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production PL/SQL Release 11.2.0.4.0 - Production CORE 11.2.0.4.0 Production TNS for Linux: Version 11.2.0.4.0 - Production NLSRTL Version 11.2.0.4.0 - Production SQL> conn hr/hr Connected. SQL> show recyclebin; SQL> drop table emptest; Table dropped. SQL> show recyclebin; ORIGINAL NAME RECYCLEBIN NAME OBJECT TYPE DROP TIME EMPTEST BIN$LyW+XZMEovjgU5XmqMB6SA==$0 TABLE 2016-03-29:08:02:22 SQL> flashback table emptest to before drop; Flashback complete. SQL> show recyclebin; SQL> 可是若是是SYS用戶刪除位於SYSTEM表空間的表，彷佛是完全刪除，不會進入回收站。具體以下： SQL> conn / as sysdba Connected. SQL> show recyclebin; SQL> create table emptest as select * from hr.employees; Table created. SQL> select table_name,tablespace_name from dba_tables where table_name='EMPTEST' and owner='SYS'; TABLE_NAME TABLESPACE_NAME EMPTEST SYSTEM SQL> drop table emptest; Table dropped. SQL> show recyclebin; SQL> SQL> flashback table emptest to before drop; flashback table emptest to before drop * ERROR at line 1: ORA-38305: object not in RECYCLE BIN 閃回報錯。 建立在其餘表空間後刪除會進入到回收站。 SQL> create table emptest tablespace users as select * from hr.employees; Table created. SQL> drop table emptest; Table dropped. SQL> show recyclebin; ORIGINAL NAME RECYCLEBIN NAME OBJECT TYPE DROP TIME EMPTEST BIN$LycThzsSsx3gU5XmqMDJHQ==$0 TABLE 2016-03-29:09:47:33