oracle创建dblink问题

1、如果在本地"D:\oracle\product\11.2.0\dbhome_1\NETWORK\ADMIN\tnsnames.ora"中设置 服务器数据库连接，必须再服务器设置同一个名字的配置：

例如：

本地

 prepaid =
 　　(DESCRIPTION =
 　　(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.100.4)(PORT = 1521))
 　　(CONNECT_DATA =
 　　(SERVER = DEDICATED)
 　　(SID = prepaid)
 　　)
 　　)

服务器

 prepaid =
 　　(DESCRIPTION =
 　　(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
 　　(CONNECT_DATA =
 　　(SERVER = DEDICATED)
 　　(SID = prepaid)
 　　)
 　　)

创建dblink的语句

 create public database link linkname connect to s_user identified by s_pwd using 'prepaid';

如果只在本地创建，查询报错：

SQL> select * from scott.emp@mylink;
select * from scott.emp@mylink
                        *
第 1 行出现错误:
ORA-12154: TNS: 无法解析指定的连接标识符

---------------------------------------------------------------

2、不设置，在创建语句中直接指定

create public database link dblinkname connect to username identified by password
　　 using '(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = database_ip)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME =servicename)
)
)';