现在进入oracle12c时代；普遍用的oracle版本为10g以上。在oracle10g之后提供了一个回收的机制。所以恢复drop表的数据以及表很容易。当然需要打开回收机制以及是归档模式。若表被drop table tablename purge;这个是闪回技术恢复不了的。现如今中国技术达人（laoxiong）提供了odu工具，让这成为现实。大家可以关注他的博客。在此感谢(laoxiong)的贡献。
就在这几天，技术老大认为数据库有几张表没用（其实另外一个平台页面有用）；叫平台的兄弟清理掉；（其实那几张表；总共也就100多条数据；清不清真的没关系，没什么影响）。清理还是drop table tablename purge。下午发现一个平台打不开。叫我恢复下数据。虽然有备份；但还是用下odu工具来恢复下。
1. 先将表空间置于offline状态。
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SQL> alter tablespace zdgame2 offline;
Tablespace altered.
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2. 然后需要使用logminer来查找被drop表的data object id：
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SQL> select group#,status from v$log;
GROUP# STATUS
---------- ----------------
1 INACTIVE
2 CURRENT
3 INACTIVE
SQL> select member from v$logfile where group#=2;
MEMBER
--------------------------------------------------
/u01/app/oradata/ora11g/redo02.log
SQL> exec sys.dbms_logmnr.add_logfile(logfilename=>'/u01/app/oradata/ora11g/redo02.log');
PL/SQL procedure successfully completed.
SQL> exec sys.dbms_logmnr.start_logmnr(options=>sys.dbms_logmnr.dict_from_online_catalog);
PL/SQL procedure successfully completed.
SQL> select scn,to_char(timestamp,'yyyymmddhh24miss'),sql_redo from v$logmnr_contents where operation='DDL' and sql_redo like '%acct_module_role%' order by 2
--在这里得到drop表的时间结点 --20151125113452
SQL> select scn,timestamp,sql_redo from v$logmnr_contents where timestamp=to_date('2015-11-25 11:34:52','yyyy-mm-dd hh24:mi:ss') order by 1;
1.0790E+12 25-NOV-15
delete from "SYS"."OBJ$" where "OBJ#" = '68199' and "DATAOBJ#" = '68199' and "OW
SCN TIMESTAMP
---------- ---------
SQL_REDO
--------------------------------------------------------------------------------
NER#" = '62' and "NAME" = 'ACCT_MODULE_ROLE' and "NAMESPACE" = '1' and "SUBNAME"
IS NULL and "TYPE#" = '2' and "CTIME" = TO_DATE('25-NOV-15', 'DD-MON-RR') and "
MTIME" = TO_DATE('25-NOV-15', 'DD-MON-RR') and "STIME" = TO_DATE('25-NOV-15', 'D
D-MON-RR') and "STATUS" = '1' and "REMOTEOWNER" IS NULL and "LINKNAME" IS NULL a
nd "FLAGS" = '0' and "OID$" IS NULL and "SPARE1" = '6' and "SPARE2" = '1' and "S
PARE3" = '62' and "SPARE4" IS NULL and "SPARE5" IS NULL and "SPARE6" IS NULL and
ROWID = 'AAAAASAABAAAP25AAI';
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下面用odu工具来恢复数据；上传软件到oracle服务器上。并解压
从oracle获取控制信息
SQL> select ts#,file#,rfile#,name from v$datafile;
把查询结果贴到control.txt；
执行./odu
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[oracle@***** odu]$ ./odu
Oracle Data Unloader:Release 3.0.8
Copyright (c) 2008,2009 XiongJun. All rights reserved.
Email: magic007cn@gmail.com
loading default config.......
byte_order little
block_size 8192
db_timezone -7
client_timezone 8
data_path data
charset_name ZHS16GBK
ncharset_name AL16UTF16
output_format text
lob_storage infile
clob_byte_order little
load control file 'config.txt' successful
loading default control file ......
ts# fn rfn bsize blocks bf offset filename
---- ---- ---- ----- -------- -- ------ --------------------------------------------
0 1 1 8192 89600 N 0 /u01/app/oradata/ora11g/system01.dbf
1 2 2 8192 76800 N 0 /u01/app/oradata/ora11g/sysaux01.dbf
2 3 3 8192 76160 N 0 /u01/app/oradata/ora11g/undotbs01.dbf
4 4 4 8192 14560 N 0 /u01/app/oradata/ora11g/users01.dbf
5 5 5 8192 2621440 N 0 /data/oradata/ora11g/******.dbf
6 6 6 8192 1310720 N 0 /data/oradata/ora11g/******.dbf
load control file 'control.txt' successful
loading dictionary data......
ODU> scan extent tablespace 5;
scan extent start: 2015-11-25 11:52:21
scanning extent...
scanning extent finished.
scan extent completed: 2015-11-25 11:52:27
ODU> unload object 68199 sample --68199是上面查出来的结果
Unloading Object,object ID: 68199, Cluster: 0
output data is in file : 'data/ODU_0000068199.txt'
Sample result:
object id: 68199
tablespace no: 5
sampled 56 rows
column count: 6
column 1 type: NUMBER
column 2 type: VARCHAR2
column 3 type: VARCHAR2
column 4 type: VARCHAR2
column 5 type: NUMBER
column 6 type: NUMBER
COMMAND:
unload object 68199 tablespace 5 column NUMBER VARCHAR2 VARCHAR2 VARCHAR2 NUMBER NUMBER
ODU> unload object 68199 tablespace 5 column NUMBER VARCHAR2 VARCHAR2 VARCHAR2 NUMBER NUMBER
Unloading Object,object ID: 68199, Cluster: 0
56 rows unloaded
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到data目录下看下是否恢复；数据都在。
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[oracle@×××××× data]$ ll
total 20
-rw-r--r-- 1 oracle dba 366 Nov 25 11:54 ODU_0000068199.ctl
-rw-r--r-- 1 oracle dba 184 Nov 25 11:54 ODU_0000068199.sql --为建表语句
-rw-r--r-- 1 oracle dba 7264 Nov 25 11:54 ODU_0000068199.txt --恢复的数据
-rw-r--r-- 1 oracle dba 773 Nov 25 11:53 sample.txt
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先建表，在用sqlldr恢复数据即可。最后把先将表空间置于online状态。alter tablespace zdgame2 online;