create public database link 名称 //(名称自定义)
connect to 用户名 identified by 密码 using '(DESCRIPTION =(ADDRESS_LIST =(ADDRESS =(PROTOCOL = TCP)(HOST = 192.168.17.254)(PORT = 1521)))(CONNECT_DATA =(SERVICE_NAME = orcl)))';
注释:HOST、SERVICE_NAME为目的库IP和数据库实例名。oracle11以上貌似自定义的名称需要用双引号引起来,例如 create public database link "dblink"