前几天，公司某项目组搭建一套演示应用系统，需要将后台的Oracle数据从一台服务器迁移到另外一套系统。在执行IMPDP导入的过程遭遇下述错误，后经查找Metalink给出解决方法。

-bash-3.2$ impdp directory=mig_dir dumpfile=dms_expdp.dmp logfile=impdp.log schemas=dms
Import: Release 10.2.0.5.0 - 64bit Production on Thursday, 10 November, 2011 3:12:56
Copyright (c) 2003, 2007, Oracle.  All rights reserved.
Username: sys/oracle as sysdba
Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
ORA-39001: invalid argument value
ORA-39000: bad dump file specification
ORA-39142: incompatible version number 3.1 in dump file "/home/oracle/mig_dir/dms_expdp.dmp"
[oracle@OEL511gR2 mig_dir]$ oerr ora 39142
39142, 00000, "incompatible version number %s in dump file \"%s\""
// *Cause:  A dump file was specified for an import operation whose version
//          number is incompatible with the dump file version of the
//          Data Pump product currently running on the system. Usually this
//          message indicates that the dump file was produced by a newer
//          version of the Data Pump export utility.
// *Action: Import this dump file using the Data Pump import utility with
//          the same version as the export which created the file.
[oracle@OEL511gR2 mig_dir]$

ORA-39142的错误是指要导入的dump file中记录的数据库版本与要导入的数据库版本不一致。果不其然，这份导出的dump file是其他同事从一套11.1.0.6.0数据库上EXPDP 导出的，而这套要导入演示系统的数据库版本是10.2.0.5.0。将11g数据库中导出的dump file导入到10g数据库的过程中，就报这个错误了，Metalink ID 553337.1给出了详细的解决方法。

我这里的解决方法是在源库，即11g的数据库上重新以EXPDP加上version=10.2.0.5.0参数重新执行导出，然后在目标库上重新执行上述导入命令，OK！

需要注意的是，经过测试：直接在目标库(10.2.0.5.0)上以IMPDP附带version=11.1.0.6.0参数导入第一份dump file文件是行不通的，依旧会报上述ORA-39142的错！
那么，dump file里包含的数据库版本信息及其它详细信息应该怎么获取呢？我们将在下一篇介绍。