在网上经常看到网友使用dblink导数据报错，报错大致如下：
$ impdp system/system network_link=DB_LINK remap_schema=A:B schemas=A
Import: Release 11.2.0.3.0 - Production on Tue Aug 14 14:07:52 2012
Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights
reserved.
Connected to: Oracle Database 11g Enterprise Edition Release
11.2.0.3.0 - 64bit Production
With the Partitioning, Real Application
Clusters, Automatic Storage Management, OLAP,
Data Mining and Real
Application Testing options
ORA-39001: invalid argument value
ORA-39200: Link name "DB_LINK" is invalid.
ORA-02019: connection
description for remote database not found
解决办法：
只需要创建public database link就ok了，dblink用完后要尽快删掉，否则可能有安全隐患。
核心步骤：
一、创建dblink
create public database link DB_LINK connect to system identified by oracle using ‘network‘;
二、impdp
impdp system/oracle network_link=network remap_schema=A:B schemas=A