答案:如何在Oracle里设置访问多个SQL Server数据库?假设我们要在ORACLE里同时能访问SQL Server里默认的pubs和Northwind两个数据库。
1、在安装了ORACLE9i Standard Edition或者ORACLE9i Enterprise Edition的windows机器上(IP:192.168.0.2), 产品要选了透明网关(Oracle Transparent Gateway)里访问Microsoft SQL Server数据库
ORACLE9I_HOMEg4msqladmin下新写initpubs.ora和initnorthwind.ora配置文件.
initpubs.ora内容如下:
HS_FDS_CONNECT_INFO="SERVER=SQLSERVER_HOSTNMAE;DATABASE=pubs"
HS_DB_NAME=pubsHS_FDS_TRACE_LEVEL=OFF
HS_FDS_RECOVERY_ACCOUNT=RECOVER
HS_FDS_RECOVERY_PWD=RECOVER
initnorthwind.ora内容如下:
HS_FDS_CONNECT_INFO="SERVER=sqlserver_hostname;DATABASE=Northwind"
HS_DB_NAME=Northwind
HS_FDS_TRACE_LEVEL=OFF
HS_FDS_RECOVERY_ACCOUNT=RECOVER
HS_FDS_RECOVERY_PWD=RECOVER
$ORACLE9I_HOME
etworkadmin 下listener.ora内容如下:
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.2)(PORT = 1521))
)
)
)
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(GLOBAL_DBNAME = test9)
(ORACLE_HOME = d:oracleora92)
(SID_NAME = test9)
)
(SID_DESC=
(SID_NAME=pubs)
(ORACLE_HOME=d:OracleOra92)
(PROGRAM=tg4msql)
)
(SID_DESC=
(SID_NAME=northwind)
(ORACLE_HOME=d:OracleOra92)
(PROGRAM=tg4msql)
)
)
|
重启动这台做gateway的windows机器上(IP:192.168.0.2)TNSListener服务.
(凡是按此步骤新增可访问的SQL Server数据库时,TNSListener服务都要重启动)
2、ORACLE8I,ORACLE9I的服务器端配置tnsnames.ora, 添加下面的内容:
pubs =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.2)(PORT = 1521))
)
(CONNECT_DATA =
(SID = pubs)
)
(HS = pubs)
)
northwind =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.2)(PORT = 1521))
)
(CONNECT_DATA =
(SID = northwind)
)
(HS = northwind) )
保存tnsnames.ora后,在命令行下
tnsping pubs
tnsping northwind
|
出现类似提示,即为成功
Attempting to contact (DESCRIPTION = (ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.2)
(PORT = 1521))) (CONNECT_DATA = (SID = pubs)) (HS = pubs))
OK(20毫秒)
Attempting to contact (DESCRIPTION = (ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.2)
(PORT = 1521)))
(CONNECT_DATA = (SID = northwind)) (HS = northwind))OK(20毫秒)
|
设置数据库参数global_names=false。
设置global_names=false不要求建立的数据库链接和目的数据库的全局名称一致。global_names=true则要求, 多少有些不方便。
oracle9i和oracle8i都可以在DBA用户下用SQL命令改变global_names参数
alter system set global_names=false;
|
建立公有的数据库链接:
create public database link pubs
connect to testuser identified by testuser_pwd using "pubs";
create public database link northwind
connect to testuser identified by testuser_pwd using "northwind";
(假设SQL Server下pubs和northwind已有足够权限的用户登陆testuser,密码为testuser_pwd)
|
访问SQL Server下数据库里的数据:
select * from stores@pubs;
...... ......select *
from region@northwind;
...... ......
|
3、使用时的注意事项
ORACLE通过访问SQL Server的数据库链接时,用select * 的时候字段名是用双引号引起来的。
例如: