删除 table:drop table 表名;
恢复删除 : flashback table 表名 to before drop;
清空table : truncate table 表名;
恢复清空:flashback table 表名 to timestamp to_timestamp('2005-05-07 15:00:00','yyyy-mm-dd hh24:mi:ss');
查询table最后修改时间:select object_name,object_type,last_ddl_time from user_objects where object_name=表名 and object_type='TABLE';
flashback原理: http://blog.itpub.net/26736162/viewspace-2136497/