创建Orcale数据库链接访问外部数据库

1. 连接到DB
sqlplus test/myDataBase@myDataBase

2. 创建数据库连接
格式: create public database link 链接的名字 connect to 用户名 identified by 密码
using'(description=(address_list=(address=(protocol=tcp)(host=主机地址)(port=1521)))(connect_data=(service_name=远程DB的名称)))'

範例:
CREATE PUBLIC DATABASE link linked_db CONNECT TO test identified BY myDataBase
 USING '(DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 127.0.0.1)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = extDB)))'

3. 访问
这样可以在myDataBase这个DB访问extDB这个DB中的表
select * from 远程DB的表明@链接的名字