使 Oracle 能同时访问多个SQL Server

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_HOMEtg4msqladmin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=RECOVERinitnorthwind.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_HOMEnetworkadmin 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，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、使用时的注重事项： 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_HOMEtg4msqladmin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:OracleOra92) (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。