这是一个鲜为人知的技巧，分享在此，希望对大家有帮助。
结论是这样的：使用exp工具的“full=y”参数生成的备份文件中，最先写入的是数据库表空间的定义信息，即使在导出的过程中遇到故障，这部分最先导出的数据依然可以被imp工具识别并抽取出其中的SQL语句。

实际验证一下这个过程。

1.使用exp工具生成备份文件
注意这里使用exp工具的“full=y”选项对system用户进行备份。
ora10g@secdb /db_backup$ exp system/oracle file=export_system.dmp full=y

Export: Release 10.2.0.1.0 - Production on Thu Mar 31 22:18:30 2011

Copyright (c) 1982, 2005, Oracle. All rights reserved.

Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options
Export done in WE8ISO8859P1 character set and AL16UTF16 NCHAR character set

About to export the entire database ...
. exporting tablespace definitions
. exporting profiles
. exporting user definitions
. exporting roles
. exporting resource costs
. exporting rollback segment definitions
. exporting database links
. exporting sequence numbers
. exporting directory aliases
. exporting context namespaces
. exporting foreign function library names
. exporting PUBLIC type synonyms
EXP-00008: ORACLE error 1013 encountered
ORA-01013: user requested cancel of current operation
EXP-00000: Export terminated unsuccessfully

在刚刚启动备份的一瞬间，我们使用“Ctrl+C”快捷键终止导出任务，获得如上的提示信息。
如果等待整个导出过程完成将非常耗时，也不是很有必要。

2.确认生成的备份文件
ora10g@secdb /db_backup$ ls -l export_system.dmp
-rw-r--r-- 1 oracle oinstall 48K Mar 31 22:18 export_system.dmp

这里显示出文件仅有48K大小，显然包含的信息很有限。

3.使用imp工具读取备份文件中的SQL语句
ora10g@secdb /db_backup$ imp system/oracle file=export_system.dmp show=y log=export_system.log full=y

Import: Release 10.2.0.1.0 - Production on Thu Mar 31 22:20:28 2011

Copyright (c) 1982, 2005, Oracle. All rights reserved.

Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options

Export file created by EXPORT:V10.02.01 via conventional path
import done in WE8ISO8859P1 character set and AL16UTF16 NCHAR character set
. importing SYSTEM's objects into SYSTEM
"CREATE UNDO TABLESPACE "UNDOTBS1" BLOCKSIZE 8192 DATAFILE '/oracle/ora10gR"
"2/oradata/ora10g/undotbs01.dbf' SIZE 293601280       AUTOEXTEND ON NEXT 524"
"2880 MAXSIZE 32767M EXTENT MANAGEMENT LOCAL "
"CREATE TABLESPACE "SYSAUX" BLOCKSIZE 8192 DATAFILE '/oracle/ora10gR2/orada"
"ta/ora10g/sysaux01.dbf' SIZE 346030080       AUTOEXTEND ON NEXT 10485760 M"
"AXSIZE 32767M EXTENT MANAGEMENT LOCAL AUTOALLOCATE ONLINE PERMANENT SEGM"
"ENT SPACE MANAGEMENT AUTO"
"CREATE TEMPORARY TABLESPACE "TEMP" BLOCKSIZE 8192 TEMPFILE '/oracle/ora10g"
"R2/oradata/ora10g/temp01.dbf' SIZE 26214400       AUTOEXTEND ON NEXT 655360"
" MAXSIZE 32767M EXTENT MANAGEMENT LOCAL UNIFORM. SIZE 1048576"
"CREATE TABLESPACE "USERS" BLOCKSIZE 8192 DATAFILE '/oracle/ora10gR2/oradat"
"a/ora10g/users01.dbf' SIZE 5242880       AUTOEXTEND ON NEXT 1310720 MAXSIZ"
"E 32767M EXTENT MANAGEMENT LOCAL AUTOALLOCATE ONLINE PERMANENT SEGMENT S"
"PACE MANAGEMENT AUTO"
"CREATE TABLESPACE "TBS_SEC_D" BLOCKSIZE 8192 DATAFILE '/oracle/ora10gR2/or"
"adata/ora10g/tbs_sec_d_01.dbf' SIZE 10485760       AUTOEXTEND ON NEXT 8192 "
" MAXSIZE 32767M EXTENT MANAGEMENT LOCAL AUTOALLOCATE ONLINE PERMANENT SE"
"GMENT SPACE MANAGEMENT AUTO"

……省略其他输出信息

IMP-00009: abnormal end of export file
Import terminated successfully with warnings.

细心观察屏幕输出的信息（或查看最终生成的export_system.log日志文件），数据库的表空间创建语句尽收眼底。与此同时在日志的最后抛出了“IMP-00009”错误，表明备份文件本身是不完整的。

重要结论得以证明：不完整的备份文件依然可以被顺利地识别，并获得其中的SQL定义信息。

4.小结
在这个重要结论的前提下，我们能做的还有很多，可以使用这个小技巧快速地获得数据库系统中的预先导出的定义信息。
在真正导出表数据之前exp工具主要完成了以下数据库定义内容的导出：
. exporting tablespace definitions
. exporting profiles
. exporting user definitions
. exporting roles
. exporting resource costs
. exporting rollback segment definitions
. exporting database links
. exporting sequence numbers
. exporting directory aliases
. exporting context namespaces
. exporting foreign function library names
. exporting PUBLIC type synonyms
. exporting private type synonyms
. exporting object type definitions
. exporting system procedural objects and actions
. exporting pre-schema procedural objects and actions
. exporting cluster definitions

数据库中以上内容均可以使用这个技巧快速的获得其SQL定义脚本。

Good luck.

secooler
11.03.30

-- The End --

【EXP/IMP】从exp工具生成的不完整备份文件中快速获取数据库表空间创建语句