使Oracle能同时访问多个SQL Server_中国IT运维网www.cnitom.com

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_HOME\tg4msql\admin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\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)。

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：

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)

    )

需要sqlserver_databaseid一致才行。