建立数据库链接 create database link

删除数据库链接：drop database link linkname;

创建数据库链接：

create database link linkname

connect to username

identified by password

using 'connection string';

如果想建立全局链接，则需要使用关键字：public

create public database link linkname

connect to username

identified by password

using 'connection string';

connection string可以有两种形式：

1，在文件tnsnames.ora配置的名称：

如：

CDRDL =

(DESCRIPTION =

(ADDRESS_LIST =

(ADDRESS = (PROTOCOL = TCP)(HOST = 10.147.129.29)(PORT = 2521))

)

(CONNECT_DATA =

(SERVICE_NAME = cdrdb)

)

)

此时可以写成：

create database link linkname

connect to username

identified by password

using 'CDRDL';

2，也可以直接使用‘=’号后面的字符串，

如：

create database link linkname

connect to username

identified by password

using '(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=10.147.129.29)(PORT=2521)))(CONNECT_DATA=(SERVICE_NAME=cdrdb)))';