1 这个目录下可以看到以下initdg4msql.ora文件，上面在安装透明网关的时候有配置的要链接SQL SERVER数据的地址和数据库名称，在这里都可以体现：

 1 # This is a customized agent init file that contains the HS parameters
 2 # that are needed for the Database Gateway for Microsoft SQL Server
 3 
 4 #
 5 # HS init parameters
 6 #
 7 HS_FDS_CONNECT_INFO=[127.0.0.1]:1433//DEMO   注：连接其他的SQL Server可修改此处
 8 HS_FDS_TRACE_LEVEL=OFF
 9 HS_FDS_RECOVERY_ACCOUNT=RECOVER
10 HS_FDS_RECOVERY_PWD=RECOVER

 1 # This is a sample listener.ora that contains the NET8 parameters that are
 2 # needed to connect to an HS Agent
 3 
 4 LISTENER =
 5  (ADDRESS_LIST=
 6       (ADDRESS=(PROTOCOL=tcp)(HOST=localhost)(PORT=1521))
 7  )
 8 
 9 SID_LIST_LISTENER=
10   (SID_LIST=
11       (SID_DESC=
12          (SID_NAME=dg4msql)
13          (ORACLE_HOME=D:Oracleproduct11.2.0dbhome_1)
14          (PROGRAM=dg4msql)
15       )
16   )
17 
18 #CONNECT_TIMEOUT_LISTENER = 0 

1 # This is a sample tnsnames.ora that contains the NET8 parameters that are
2 # needed to connect to an HS Agent
3 
4 dg4msql  =
5   (DESCRIPTION=
6     (ADDRESS=(PROTOCOL=tcp)(HOST=localhost)(PORT=1521))
7     (CONNECT_DATA=(SID=dg4msql))
8     (HS=OK)
9   ) 

 1 # This is a sample listener.ora that contains the NET8 parameters that are
 2 # needed to connect to an HS Agent
 3 SID_LIST_LISTENER =
 4   (SID_LIST =
 5     (SID_DESC =
 6       (SID_NAME = CLRExtProc)
 7       (ORACLE_HOME = D:Oracleproduct11.2.0dbhome_1)
 8       (PROGRAM = extproc)
 9       (ENVS = "EXTPROC_DLLS=ONLY:D:Oracleproduct11.2.0dbhome_1inoraclr11.dll")
10     )
11     (SID_DESC=
12          (SID_NAME=dg4msql)
13          (ORACLE_HOME=D:Oracleproduct11.2.0dbhome_1)
14          (PROGRAM=dg4msql)
15     )
16   )
17 
18 LISTENER =
19   (DESCRIPTION_LIST =
20     (DESCRIPTION =
21       (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
22       (ADDRESS = (PROTOCOL = TCP)(HOST = YRDLG5GS4G3ODYI)(PORT = 1521))
23       (ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1)(PORT=1521))
24     )
25   )
26 
27 ADR_BASE_LISTENER = D:Oracle
28 
29 #CONNECT_TIMEOUT_LISTENER = 0 

1 这里需要注意的主要是一下几点：
2 PROGRAM为dg4msql：因为实例的配置文件在dg4msql目录下，就是上面的initdg4msql.ora文件所在的目录
3 SID_NAME为dg4msql：这个sid就是上面的文件名中的sid，initdg4msql.ora的sid为dg4msql
4 ORACLE_HOME就是我们透明网关的安装目录
5 ORACLE的监听端口是1521，我的oracle和透明网关是安装在同一台机器上的，所以透明网关的监听端口设置为1522。
6 一个initSID.ora文件就对应一个SID_DESC，可以根据想要链接的数据库来配置。

 1 # sqlnet.ora Network Configuration File: D:Oracleproduct11.2.0dbhome_1
etworkadminsqlnet.ora
 2 # Generated by Oracle configuration tools.
 3 
 4 # This file is actually generated by netca. But if customers choose to 
 5 # install "Software Only", this file wont exist and without the native 
 6 # authentication, they will not be able to connect to the database on NT.
 7 
 8 SQLNET.AUTHENTICATION_SERVICES= (NONE)
 9 
10 NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)

 1 # This is a sample tnsnames.ora that contains the NET8 parameters that are
 2 # needed to connect to an HS Agent
 3 ORCL =
 4   (DESCRIPTION =
 5     (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
 6     (CONNECT_DATA =
 7       (SERVER = DEDICATED)
 8       (SERVICE_NAME = orcl)
 9     )
10   )
11 
12 dg4msql  =
13   (DESCRIPTION=
14     (ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1)(PORT=1521))
15     (CONNECT_DATA=(SID=dg4msql))
16     (HS=OK)
17   ) 

1 命令：lsnrctl reload

1 SELECT * FROM user_sys_privs where privilege like upper('%DATABASE LINK%')

1 如：grant create public database link to system ;
2 格式：grant create public database link to 用户名 ;

1 查询dblink：
2 select * from dba_db_links;
3 
4 删除dblink：
5 DROP DATABASE LINK [name];  

 1 create database link DBTEST1
 2   connect to SA identified by "password"
 3   using 'dg4msql';
 4 
 5 
 6 
 7 格式：
 8 create database link DBLink名称
 9   connect to SQL Server账户 identified by "SQL Server密码"
10   using 'SID';