基本步骤
说明：
HostName：dmserver
Win2000 Server Oracle Database 9.2.0.1.0 Microsoft SQL Server 2000
UserName:User Password:User
Database:CFDai TableName:Test
都使用 tcp/ip 默认端口1521
基本步骤：
1: 安装 TRANSPARENT GATEWAY FOR MSSQL选件，输入主机名和数据库名
安装完后，在d:\oracle\ora92的目录下产生一个目录D:\oracle\ora92\tg4msql
同时，自动生成文件：inittg4msql.ora
其中内容为：
HS_FDS_CONNECT_INFO=dmserver.CFDai #服务器名.数据库名
HS_FDS_TRACE_LEVEL=OFF
HS_FDS_RECOVERY_ACCOUNT=RECOVER
HS_FDS_RECOVERY_PWD=RECOVER
注：第一行可写为HS_FDS_CONNECT_INFO="dmserver;DATABASE=CFDai"
2: 配置 LISTENER.ORA
SID_LIST_LISTENER =
(SID_LIST =
……
(SID_DESC =
(GLOBAL_DBNAME = tg4msql) #可重命名
(PROGRAM = tg4msql)
(SID_NAME = tg4msql) #可重命名
(ORACLE_HOME = D:\oracle\ora92) #数据库主目录名
)
)
3: 停止并重启 DATABASE 和 LISTENER服务
4: 配置 tnsnames.ora，在文件尾增加以下内容：
tg4msql =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = dmserver)(PORT = 1521))
)
(CONNECT_DATA =
(SID = tg4msql)
)
(HS=OK)
)
5: 在SQL Plus或SQLPlus Worksheet中通过如下语句建立数据库连接
CREATE PUBLIC DATABASE LINK DB_SQL CONNECT TO User IDENTIFIED by User USING 'tg4msql';
6: 在SQL Plus或SQLPlus Worksheet中测试
select * from test@DB_SQL;
7：取消数据库连接
DROP PUBLIC DATABASE LINK DB_SQL;
FW:多谢！我也刚刚搞定。
原来是一个低级错误――tnsnames.ora文件配置错误（直接拷贝后修改，结果没改主机地址！指到别的地方了：）：））。另外注意：lsnrctl中显示status=unknow不必惊讶，正常。
今天阅读了Oracle 9i附带的Oracle Transparent Gateways文档，整理了一下，供参考！
搜索关键字：
Oracle Transparent Gateways
透明网关
Oracle database applications can be executed against non-Oracle database servers using SQL*Connect or the Oracle Open Gateway.
Oracle Transparent Gateways
The capabilities, SQL mappings, data type conversions, and interface to the remote non-Oracle system are contained in the gateway. The gateway interacts with Heterogeneous Services to provide the transparent connectivity between Oracle and non-Oracle systems.
The gateway can be installed on any machine. It can be on the same machine as the Oracle database or on the same machine as the non-Oracle system or on a third machine as a standalone. Each configuration has its advantages and disadvantages. The issues to consider when determining where to install the gateway are network traffic, operating system platform availability, hardware resources and storage.
Configuring the Gateway
After installing the gateway(supplied with Oracle 9i setup package), perform the following tasks to configure the gateway for Microsoft SQL Server:
1.Configuring the Gateway(ORACLE_HOME\tg4msql\admin\init.ora on gateway side)
2.Configuring Oracle Net Services Listener for the Gateway(listener.ora on gateway side)
3.Configuring the Oracle Database Server for Gateway Access(tnsnames.ora on oracle side)
4.Creating Database Links(on oracle side)
1.Configuring the Gateway
Task 1: Choose a System Identifier for the Gateway
The gateway system identifier (SID) is an alphanumeric character string that identifies a gateway instance.The SID is used as part of the file name for the initialization parameter file.
Task 2: Customize the Initialization Parameter File
The initialization parameter file must be available when the gateway is started.
如：ORACLE_HOME\tg4msql\admin\initmytg4msql.ora
注意：HS_FDS_CONNECT_INFO= server_name.database_name
HS_FDS_DEFAULT_OWNER = 缺省用户
2.Configuring Oracle Net Services Listener for the Gateway
The gateway requires Oracle Net Services to provide transparent data access. After configuring the gateway, configure Oracle Net Services to work with the gateway.
Configure Oracle Net Services TNS Listener for the Gateway
If you are already running a TNS listener that listens on multiple database SIDs, add only the following syntax to SID_LIST in the existing listener.ora file:
SID_LIST_LISTENER=
(SID_LIST=
(SID_DESC=.
.
)
(SID_DESC=.
.
)
(SID_DESC=
(SID_NAME=mytg4msql)
(ORACLE_HOME=oracle_home_directory)
(PROGRAM=tg4msql)
)
)
3.Configuring the Oracle Database Server for Gateway Access
Before you use the gateway to access Microsoft SQL Server data you must configure the Oracle database server to enable communication with the gateway over Oracle Net Services.
Configuring Oracle Net Services for the Oracle Database Server
The tnsnames.ora file is required by the Oracle database server accessing the gateway, but not by the gateway. Edit the tnsnames.ora file to add a connect descriptor for the gateway.:
connect_descriptor=
(DESCRIPTION=
(ADDRESS=
(PROTOCOL=TCP)
(HOST= host_name)
(PORT= port_number)
)
(CONNECT_DATA=
(SID= mytg4msql))
(HS=OK))--(HS=OK) specifies that this connect descriptor uses the Oracle Heterogeneous Services option.
4.Creating Database Links
接下来：Configuring the Gateway for Multiple Microsoft SQL Server Databases
1.Configuring the Gateway
Create Two Initialization Parameter Files
cd ORACLE_HOME\tg4msql\admin
copy inittg4msql.ora inittg4msql2.ora
copy inittg4msql.ora inittg4msql3.ora
Change the value of the HS_FDS_CONNECT_INFO parameter in the new files.
For inittg4msql2.ora, enter the following:
HS_FDS_CONNECT_INFO=msql_nt2.db2
For inittg4msql3.ora, enter the following:
HS_FDS_CONNECT_INFO=msql_nt3.db3
2.Configuring Oracle Net Services Listener for the Gateway
Add Entries to listener.ora
Add two new entries to the TNS listener configuration file, listener.ora.
SID_LIST_LISTENER=
(SID_LIST=
(SID_DESC=
(SID_NAME=tg4msql)
(ORACLE_HOME= oracle_home_directory)
(PROGRAM=tg4msql)
)
(SID_DESC=
(SID_NAME=tg4msql2)
(ORACLE_HOME= oracle_home_directory)
(PROGRAM=tg4msql)
)
(SID_DESC=
(SID_NAME=tg4msql3)
(ORACLE_HOME= oracle_home_directory)
(PROGRAM=tg4msql)
)
)
3.Configuring the Oracle Database Server for Gateway Access
tnsnames.ora ：
old_db_using=(DESCRIPTION=
(ADDRESS=
(PROTOCOL=TCP)
(PORT=1541)
(HOST=gtwhost))
(CONNECT_DATA=
(SID=tg4msql))
(HS=OK))
new_db2_using=(DESCRIPTION=
(ADDRESS=
(PROTOCOL=TCP)
(PORT=1541)
(HOST=gtwhost))
(CONNECT_DATA=
(SID=tg4msql2))
(HS=OK))
new_db3_using=(DESCRIPTION=
(ADDRESS=
(PROTOCOL=TCP)
(PORT=1541)
(HOST=gtwhost))
(CONNECT_DATA=
(SID=tg4msql3))
(HS=OK))
4.Creating Database Links
