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)里要访问Microsoft SQL Server数据库.

$ORACLE9I_HOME\tg4msql\admin下新写initpubs.ora和initnorthwind.ora配置文件
[align=left]initpubs.ora内容如下:[/align]
HS_FDS_CONNECT_INFO="SERVER=sqlserver_hostname;DATABASE=pubs"

HS_DB_NAME=pubs

HS_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

(蓝色字的部分可以根据具体要访问的SQL Server数据库的情况而修改)

$ORACLE9I_HOME\network\admin 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:\oracle\ora92)

(SID_NAME = test9)

)

(SID_DESC=

(SID_NAME=pubs)

(ORACLE_HOME=d:\Oracle\Ora92)

(PROGRAM=tg4msql)

)

(SID_DESC=

(SID_NAME=northwind)

(ORACLE_HOME=d:\Oracle\Ora92)

(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)
[align=left]2、ORACLE8I，ORACLE9I的服务器端配置tnsnames.ora, 添加下面的内容:[/align]
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：
[align=left]global_names=false[/align]

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
[align=left]alter system set global_names=false;[/align]

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录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：
create table stores as select * from stores@pubs;

select zip from stores；

ERROR 位于第 1 行:

ORA-00904: 无效列名

select "zip" from stores;

zip

-----

98056

92789

96745

98014

90019

89076

已选择6行。

用SQL Navigator或Toad看从SQL Server转移到ORACLE里的表的建表语句为:
CREATE TABLE stores

("stor_id" CHAR(4) NOT NULL,

"stor_name" VARCHAR2(40),

"stor_address" VARCHAR2(40),

"city" VARCHAR2(20),

"state" CHAR(2),

"zip" CHAR(5))

PCTFREE 10

PCTUSED 40

INITRANS 1

MAXTRANS 255

TABLESPACE users

STORAGE (

INITIAL 131072

NEXT 131072

PCTINCREASE 0

MINEXTENTS 1

MAXEXTENTS 2147483645

)

/

总结: windows下ORACLE9i网关服务器在$ORACLE9I_HOME\tg4msql\admin目录下的initsqlserver_databaseid.ora

WINDOWS下ORACLE9i网关服务器listener.ora里面

(SID_DESC=

(SID_NAME=sqlserver_databaseid)

(ORACLE_HOME=d:\Oracle\Ora92)

(PROGRAM=tg4msql)

)
UNIX或WINDOWS下ORACLE8I,ORACLE9I服务器tnsnames.ora里面

northwind =

(DESCRIPTION =

(ADDRESS_LIST =

(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.2)(PORT = 1521))

)

(CONNECT_DATA =

(SID = sqlserver_databaseid)

)

(HS = sqlserver_databaseid)

)

sqlserver_databaseid一致才行.
[align=left] [/align]