Creating a database link to SQL server

Hi All,
How can I create a database link from Oracle9i Enterprise Edition Release 9.2.0.1.0 DB to MS SQL Server database.
Thanking You
Regards Lakmal

It depends on your requirements.
You can use either Generic Connectivity or Transparent Gateways.
More information can be found here:
http://www.oracle.com/technology/products/gateways/index.html

Similar Messages

How to create a database link to SQL Server from a RAC environment

We have a 4 node RAC running 11.2.0.3 binaries on 64-bit linux.
Grid owns the listener named listener.
Oracle owns the database.

Thanks all! But I tried to configure and I am getting
TNS-01201: Listener cannot find executable /u01/app/oracle/product/11.2.0.3/dbhome_1/bin/InfoEdb10 for SID InfoEdb10
Listener failed to start. See the error message(s) above...
So! What I did was
1. Configure the odbc from the OS (only one node) and create the DSN and its odbc files. connectivity works from Operating Systems.
2. Create the listener entry (under GRID) user.
3. Create the remotedb.ora file under $ORACLE_HOME/hs/admin
--- Here is listener.ora file
LISTENER_NODE1_TG =
   (DESCRIPTION_LIST =
    (DESCRIPTION =
       (ADDRESS = (PROTOCOL = TCP)(HOST = devrac-a-01-vip.cssd.pitt.edu)(PORT = 1549)(IP = FIRST))
       (ADDRESS = (PROTOCOL = TCP)(HOST = devrac-a-01.cssd.pitt.edu)(PORT = 1549)(IP = FIRST))
SID_LIST_LISTENER_NODE1_TG =
   (SID_LIST =
       (SID_DESC =
         (SID_NAME = InfoEdb10)
         (ORACLE_HOME = /u01/app/oracle/product/11.2.0.3/dbhome_1)
         (ENVS = "LD_LIBRARY_PATH=/u01/app/oracle/product/11.2.0.3/dbhome_1/lib")
         (PROGRAM = InfoEdb10)
any help is appreciated

Database link to SQL Server Init error

Hi all,
i´m tryng to create a dblink between Oracle 10.2.0 in a RHEL4 and a SQL Server.
I can connect using isql but when i try using sqlplus i obtain this error:
SQL> CREATE DATABASE LINK dbl
CONNECT TO "user"
IDENTIFIED BY "pwd"
USING 'hsodbc'; 2 3 4
Enlace con la base de datos creado.
SQL> SELECT * FROM Table_1@dbl;
SELECT * FROM Table_1@dbl
ERROR en línea 1:
ORA-28545: error diagnosticado por Net8 al conectar a un agente (error in Net8 while connecting an agent)
Unable to retrieve text of NETWORK/NCR message 65535
ORA-02063: 2 lines precediendo a DBL
This is the error explanantion in Oracle Docs:
I think the problem is the ini file inithsodbc.ora.
inithsodbc.ora
# This is a sample agent init file that contains the HS parameters that are
# needed for an ODBC Agent.
# HS init parameters
# AAB - Parametros para asociar un agente ODBC al HS
HS_FDS_CONNECT_INFO = MSQLS
HS_FDS_TRACE_LEVEL = ON
HS_FDS_SHAREABLE_NAME =/usr/local/freetds/lib/libtdsodbc.so
HS_AUTOREGISTER = true
# ODBC specific environment variables
set ODBCINI=/home/oracle/.odbc.ini
listener.ora
# listener.ora Network Configuration File: /app/oracle/oracle/product/10.2.0/db_1/network/admin/listener.ora
# Generated by Oracle configuration tools.
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = STA2)
(ORACLE_HOME = /app/oracle/oracle/product/10.2.0/db_1)
     (SID_DESC = (SID_NAME=hsodbc)
(ORACLE_HOME=/app/oracle/oracle/product/10.2.0/db_1)
(PROGRAM=hsodbc)
                         (ENVS=LD_LIBRARY_PATH=/app/oracle/oracle/product/10.2.0/db_1/lib:/usr/local/lib)
LISTENER =
     (DESCRIPTION =
     (ADDRESS_LIST =
          (ADDRESS = (PROTOCOL = TCP)(HOST = nemesisgr2.hi.inet)(PORT = 1521))
tnsnames.ora
# tnsnames.ora Network Configuration File: /app/oracle/oracle/product/10.2.0/db_1/network/admin/tnsnames.ora
# Generated by Oracle configuration tools.
DEVSTA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = nemesisgr.hi.inet)(PORT = 1521))
(CONNECT_DATA =
(SERVICE_NAME = devSTA)
STA2 =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = nemesisgr2.hi.inet)(PORT = 1521))
(CONNECT_DATA =
(SERVICE_NAME = STA2)
EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
(CONNECT_DATA =
(SID = PLSExtProc)
(PRESENTATION = RO)
STA =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = nemesisgr2.hi.inet)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = STA)
#AAB - Descripcion de servicio para conectar con SQLServer
HSODBC = (DESCRIPTION=
(ADDRESS=(PROTOCOL=tcp)
(HOST=nemesisgr2.hi.inet)
(PORT=1521)
(CONNECT_DATA = (SID=hsodbc)
(HS = OK)
ODBC Files
odbc.ini
[ODBC Data Sources]
MSQLS = Microsoft SQL Server
[MSQLS]
Driver = /usr/local/freetds/lib/libtdsodbc.so
Description = Microsoft SQL Server
Trace = No
Servername = sqlserver
Database = master
[Default]
Driver = /usr/local/freetds/lib/libtdsodbc.so
odbcinst.ini
[PostgreSQL]
Description          = ODBC for PostgreSQL
Driver          = /usr/lib/libodbcpsql.so
Setup          = /usr/lib/libodbcpsqlS.so
FileUsage          = 1
[MSQLSDRIVER]
Description          = Driver for MS SQL Server
Driver          = /usr/local/freetds/lib/libtdsodbc.so
Setup          = /usr/lib64/libtdsS.so
FileUsage          = 1
UsageCount          = 5
freetds.conf
# $Id: freetds.conf,v 1.12 2007/12/25 06:02:36 jklowden Exp $
# This file is installed by FreeTDS if no file by the same
# name is found in the installation directory.
# For information about the layout of this file and its settings,
# see the freetds.conf manpage "man freetds.conf".
# Global settings are overridden by those in a database
# server specific section
[global]
# TDS protocol version
;     tds version = 4.2
     # Whether to write a TDSDUMP file for diagnostic purposes
     # (setting this to /tmp is insecure on a multi-user system)
;     dump file = /tmp/freetds.log
;     debug flags = 0xffff
     # Command and connection timeouts
;     timeout = 10
;     connect timeout = 10
     # If you get out-of-memory errors, it may mean that your client
     # is trying to allocate a huge buffer for a TEXT field.
     # Try setting 'text size' to a more reasonable limit
     text size = 64512
# A typical Sybase server
[egServer50]
     host = symachine.domain.com
     port = 5000
     tds version = 5.0
# A typical Microsoft server
[egServer70]
     host = ntmachine.domain.com
     port = 1433
     tds version = 7.0
# Test MS SQl Server
[sqlserver]
     Database = master
     host = pruebas.hi.inet
     port = 1433
     tds version = 7.0
Any ideas??
Thanks in advance.
Alex

I have changed the inithsodbc.ora file including:
HS_FDS_SHAREABLE_NAME =/usr/lib/libodbc.so (I have ODBC installed)
Here you are the other information:
lsnrctl status
LSNRCTL for Linux: Version 10.2.0.1.0 - Production on 23-OCT-2008 09:29:52
Copyright (c) 1991, 2005, Oracle. All rights reserved.
Bienvenido a LSNRCTL, escriba "help" para obtener información.
LSNRCTL> status
Conectándose a (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=nemesisgr2.hi.inet)(PORT=1521)))
ESTADO del LISTENER
Alias LISTENER
Versión TNSLSNR for Linux: Version 10.2.0.1.0 - Production
Fecha de Inicio 22-OCT-2008 19:31:34
Tiempo Actividad 0 días 13 hr. 58 min. 29 seg.
Nivel de Rastreo off
Seguridad ON: Local OS Authentication
SNMP OFF
Parámetros del Listener /app/oracle/oracle/product/10.2.0/db_1/network/admin/listener.ora
Log del Listener /app/oracle/oracle/product/10.2.0/db_1/network/log/listener.log
Recibiendo Resumen de Puntos Finales...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=nemesisgr2)(PORT=1521)))
Resumen de Servicios...
El servicio "STA" tiene 1 instancia(s).
La instancia "STA", con estado READY, tiene 1 manejador(es) para este servicio...
El servicio "STA2" tiene 2 instancia(s).
La instancia "STA2", con estado UNKNOWN, tiene 1 manejador(es) para este servicio...
La instancia "STA2", con estado READY, tiene 1 manejador(es) para este servicio...
El servicio "STA2XDB" tiene 1 instancia(s).
La instancia "STA2", con estado READY, tiene 1 manejador(es) para este servicio...
El servicio "STA2_XPT" tiene 1 instancia(s).
La instancia "STA2", con estado READY, tiene 1 manejador(es) para este servicio...
El servicio "STAXDB" tiene 1 instancia(s).
La instancia "STA", con estado READY, tiene 1 manejador(es) para este servicio...
El servicio "STA_XPT" tiene 1 instancia(s).
La instancia "STA", con estado READY, tiene 1 manejador(es) para este servicio...
El servicio "hsodbc" tiene 1 instancia(s).
La instancia "hsodbc", con estado UNKNOWN, tiene 1 manejador(es) para este servicio...
El comando ha terminado correctamente
LSNRCTL>
hsodbc
There is no output executing this command.
[oracle@nemesisgr2 ~]$ /app/oracle/oracle/product/10.2.0/db_1/bin/hsodbc
[oracle@nemesisgr2 ~]$
tnsping hsodbc
[oracle@nemesisgr2 ~]$ tnsping hsodbc
TNS Ping Utility for Linux: Version 10.2.0.1.0 - Production on 23-OCT-2008 09:35:58
Copyright (c) 1997, 2005, Oracle. All rights reserved.
Archivos de parámetros utilizados:
/app/oracle/oracle/product/10.2.0/db_1/network/admin/sqlnet.ora
Adaptador TNSNAMES utilizado para resolver el alias
Attempting to contact (DESCRIPTION= (ADDRESS=(PROTOCOL=tcp) (HOST=nemesisgr2.hi.inet) (PORT=1521)) (CONNECT_DATA = (SID=hsodbc)) (HS = OK))
Realizado correctamente (40 mseg)
Rgds,
Alex

Strange problem with an Oracle database link to SQL Server

Hi gurus,
Please help me on this problem.
We have an Oracle 10R2 database link to a SQL Server 2000 database. I can select count(*) from The_SQL_Server_Table@myOracleLink, and I can describe The_SQL_Server_Table@myOracleLink, but I cannot select Column1 from The_SQL_Server_Table@myOracleLink! I am getting the ORA-00904: "COLUMN1": invalid identifier error.
Could anyone tell me what is wrong here? By the way, the same user name can select all the columns in The_SQL_Server_Table through ODBC from the client app. But I need the DB link to work with some Oracle stored functions.
Thank you!
Ben

myora9i wrote:
Hi gurus,
Please help me on this problem.
We have an Oracle 10R2 database link to a SQL Server 2000 database. I can select count(*) from The_SQL_Server_Table@myOracleLink, and I can describe The_SQL_Server_Table@myOracleLink, but I cannot select Column1 from The_SQL_Server_Table@myOracleLink! I am getting the ORA-00904: "COLUMN1": invalid identifier error.
Could anyone tell me what is wrong here? By the way, the same user name can select all the columns in The_SQL_Server_Table through ODBC from the client app. But I need the DB link to work with some Oracle stored functions.
Thank you!
Bennotice "COLUMN1" is different from "Column1"
CaSe MaTTerS!

Multibyte issue in database link with sql server

Hi Gurus,
Greetings!!!
I need to transfer data from Microsoft SQL Server 2005 to Oracle DAtabase 10g(AL32UTF8 characterset). I achieved it using Heterogeneous Connectivity. I can now issue queries but unfortunately i got an issue in displaying multibyte characters. I thought of using another Tool that can display multibyte data but it did not help. I even tried setting the initialization parameter HS_LANGUAGE to different characterset but still not able to display. Kindly help and advise how to resolve the said issue.
Many Thanks in Advance,
Benjie

What is the exact issue you're talking about?
Can you explain it or show us a sort of it with a sample output?
MS SQL Server is not our daily bread so we may not know how it works with Oracle and what problems are there in their interconnectivity, but we may tell you what may be the reason of a behavior that causes the issues for your purpose.
Bye Alessandro

DATABASE LINK FOR SQL SERVER

Hi all,
We are running SAP 4.7C with oracle database. For other oracle (non-sap) we are using DBCO to get/put data. Now we have to do the same in SQL server also. In addition to SAP standard table we are sending data of customer table (Z & Y series). Can anybody guide me how to send / receive data using bapi/rfc or some other method.
regards
balakumar

Hi!
For using native-SQL with MSSQL database you have to make your database requests from application server resides on windows platform. So, your basis people have to set up one more windows-based application server instance. There is no impact on backend R/3 database.
Regards,
Maxim.

Not able to create a database link using the database gateway of oracle 11g

HI,
While trying to create a database link to SQL server from Oracle ,using the database gateway provided with 11g, i am getting the following error while making use of it in selecting columns from tables :
Error starting at line 1 in command:
select * from test1@dblink
Error at Command Line:1 Column:20
Error report:
SQL Error: ORA-28513: internal error in heterogeneous remote agent
ORA-02063: preceding line from DBLINK
These are the steps i have followed for setting up:
1.Ran the set up for the Database gateway.and mentioned the SQL server name and database .ALos set up a listener.
2. Added the following in the Listener.ora of Oraclehome 11/NETWORK/ADMIN:
LISTENER_SQL_FCD =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST =localhost) (PORT = 1541)
SID_LIST_LISTENER_SQL_FCD =
(SID_LIST =
(SID_DESC =
(SID_NAME=dg4msql)
(ORACLE_HOME= D:\app\20537\product\11.1.0\db_3)
(PROGRAM=dg4msql)
3.Added the following in tnsnames.ora inOracle home/NETWORK/ADMIN:
dg4msql=
(DESCRIPTION=
(ADDRESS=(PROTOCOL=tcp)(HOST=localhost)(PORT=1541))
(CONNECT_DATA=(SID=dg4msql))
(HS=OK)
4. Following is the entry in initdg4msql.ora in C:\product\11.1.0\tg_5\dg4msql\admin:
HS_FDS_CONNECT_INFO=10.148.45.242:1433//SalesDemo
HS_FDS_TRACE_LEVEL=DEBUG
HS_FDS_RECOVERY_ACCOUNT=RECOVER
HS_FDS_RECOVERY_PWD=RECOVER
5. Created the database link :
create database link dblink
connect to "sa" identified by "<pswd>"
using 'dg4msql'
On running :select * from test1@dblink i get the following error:
Error starting at line 1 in command:
select * from test1@dblink
Error at Command Line:1 Column:20
Error report:
SQL Error: ORA-28513: internal error in heterogeneous remote agent
ORA-02063: preceding line from DBLINK
Is there any issue with the set or definition that I get the above error?

What is the version of the Oracle database in which you have specified/and use the database link?
If it is for example 10.2.0.3.0 you need to apply the mandatory patch for RDBMS bug 5965763 first before being able to use an 11g gateway. Have a look at MetaLink note 457808.1 for details about this patch.
Regards,
Ed

DB Link to SQL Server (11gR2 64-bit Windows 7)

Without going into all the gruesome details, it is mostly straightforward to set up a DB Link to SQL Server from an Oracle 10 instance on 32 bit Windows 7. However I simply cannot get the link to work on 11gR2. I tried the simplistic ds4odbc interface and the more complex SQL Server gateway. Nothing works. The connection always times out. Has anyone been able to create a SQL Server DB link from 11gR2 on Windows 7? (The Oracle instance is 32 bit. The OS is 64 bit). I know Win7 is unsupported at present.
Edited by: user2190753 on Oct 14, 2010 4:51 PM

Hi,
first of all you need to check the ODBC connectivity between Oracle and SQL Server and the Data source,try to load data from oracle to Sql Server to check the ODBC connection is working properly and then create database link from sql server to oracle ,you can create stored procedures in SQL server to get data from Oracle to sql server or Oracle PL/SQL Packages to data from sql server to Oracle Database
To setup ODBC and datasource
see this link
http://www.databasejournal.com/features/oracle/article.php/3442661/Making-a-Connection-from-Oracle-to-SQL-Server.htm
and then create link server in sql server after you test connenction with oracle

Error in Creating a Database Link

I am trying to create a database link in SQL Workshop but unavailbe to create one because of the error below:
Create Database Link Failed.
ORA-00933: SQL command not properly ended
Hope you can help me with this. Thanks!

788818 wrote:
I am trying to create a database link in SQL Workshop but unavailbe to create one because of the error below:
Create Database Link Failed.
ORA-00933: SQL command not properly ended
Hope you can help me with this. Thanks!Not really, because the error message you have posted generally relates to a syntax or typing error and you haven't posted any other information. We need version of the DB and the text of what you are trying to do. But before you post that, have you tried the documentation?
Regards
Andre

ODBC Link ans SQL Server

Hi!
So I tried to create a ODBC link with SQL server, but there is a problem during the authentification process.
When I try to use authentification thanks to SQL server, even with 'sa' user enabled, this error shows up
Connection failed:
SQLState: '28000'
SQL Server Error: 18456
[Microsoft][ODBC SQL Server Driver][SQL Server]Login failed for user 'myUser'.
When I try to use authentification with Windows ID, another error shows up :
Connection faled:
SQLState: '28000'
SQL Server Error: 18452
[Microsoft][ODBC SQL Server Driver][SQL Server]Login failed. The login is from an untrusted domain and cannot be used with Windows authentication.
The server is a VPS server and there is no domain to configure.
I already tried to switch to mixed authentification, with it I can easily connect to SQL server with SQL server Management Studio. I also already browsed SQL Server Configuration Manager in order to set a static (not dynamic) port, TCP/IP are enabled in SQL
server Network Configuration / Protocols for SQLEXPRESS but it still doesn't work. Ofc I restarted SQL server several times and I even tried to uninstall/reinstall it.
Finally, this error shows up when I start SQL Server agent with SQL server Configuration Manager.
>The request failed or the service did not respond in a timely fashion. Consult the event log or other applicable error logs for details.
I tried to find out what is the problem by reading the logs but there is nothing about the failed authentification attempts there. It only shows some services starting or stopping.
I read somewhere that it the VIA protocol could be the problem, but I can't find it anywhere in SQL Server Configuration Manager.
I've been struggling for days with this. you're my only hope
thanks!

I juste forgot to explain that I have to do this for a client who will use a software of my company and this software needs this ODBC link to communicate with SQL Server. Also the users will connect to the server in TSE (so the application will be on the
same server than SQL Server). I don't know if this detail is important but I prefer specify.
"If it works in SSMS to connect with a SQL Login, then it should work with ODBC by using the same server name/credentials from the sam Client."
I entered 'sa' user and another user that I created in SQL Server but I have the same error (login fail for user)
"Are remote Connections enabled? Is a Firewall running on server and/or Client side? If so unblock the required TCP and UDP ports."
Remote Connections are enabled on the server and there's just Windows Firewall on the server. I unblocked resquired TCP and UDP Ports. Even with the Windows Firewall turned off I have this problem.

How to create a database link ?

i want to create a database link.please give mesteps

There is a chapter in the DBA Administration manual for versions 8.1, 9.2, and 10g on this topic which provide all the information you need.
You will need to choose the type of database link: global, current user, or imbedded user and if you need a public or private link.
Basically all you do is create a tnsnames.ora entry for the remote db and then create a database link (See SQL manual entry CREATE DATABASE LINK) that references the tnsnames.ora entry.
The manuals or the entire manual set can be downloaded from technet.
HTH -- Mark D Powell --

How could I create a "Linked Server" link from SQL Server 2008R2 64-Bit to Oracle Database 11.2 64-Bit?

How could I create a "Linked Server" link from SQL Server 2008R2 64-Bit to Oracle Database 11.2 64-Bit?
Let's say the SQL Server and Oracle Database are in the same Company Internet Network.
I have the code, but I do not know how to use it. Such as what is System DSN Name? Where could I get it. What does it look like?
Do I need to install any Oracle Client Software in order to link from SQL Server to Oracle? Or SQL Server has the built-in drivers installed already that I can directly create a Linked Server from SQL Server to Oracle?
I need to know details. Thanks.
USE master
go
EXEC sp_addlinkedserver
     @server  = '{Linked Server Name}'
    ,@srvproduct = '{System DSN Name}'
    ,@provider  = 'MSDASQL'
    ,@datasrc  = '{System DSN Name}'
EXEC sp_addlinkedsrvlogin
     @rmtsrvname = '{Linked Server Name}'
    ,@useself  = 'False'
    ,@locallogin = NULL
    ,@rmtuser  = '{Oracle User Name}'
    ,@rmtpassword = '{Oracle User Password}'

You need an OLE DB provider for Oracle. There is one that ships with Windows, but it only supports very old versions of Oracle. Oracle has an OLE DB provider that you can use. I don't know if it's part of Oracle Client or how it is bundled.
You should not use MSDASQL or any DSN.
Erland Sommarskog, SQL Server MVP, [email protected]

ERROR WHILE CREATING A DATABASE LINK USING HETEROGENEOUS SERVICES

I'm creating a database link with the Oracle Dataware Builder, and i get the following error:
Probando...
Fallo.
SQL Exception
Error del repositorio: Excepción SQL.
Nombre de la Clase: CacheMediator.
Nombre del Método: getDDEntryFromDB.
Mensaje de Error del Repositorio: ORA-28500: connection from ORACLE to a non-Oracle system returned this message:
[Generic Connectivity Using ODBC][Informix][Informix ODBC Driver][Informix]Incorrect password or user [email protected] is not known on the database server. (SQL State: 28000; SQL Code: -951)
ORA-02063: preceding 2 lines from PRUEBA_SEH
As you can see i'm using heterogeneus services to connect to a informix database. ALTIADM is a valid user for that database, i don't send my ip address 192.168.0.62, but the error says "[email protected] is not known in the database server". how can i solve it?????

Right places to ask this question are
Heterogeneous Connectivity
Warehouse Builder

ERROR WHILE CREATING A DATABASE LINK TO INFORMIX

I'm creating a database link with the Oracle Dataware Builder, and i get the following error:
Probando...
Fallo.
SQL Exception
Error del repositorio: Excepción SQL.
Nombre de la Clase: CacheMediator.
Nombre del Método: getDDEntryFromDB.
Mensaje de Error del Repositorio: ORA-28500: connection from ORACLE to a non-Oracle system returned this message:
[Generic Connectivity Using ODBC][Informix][Informix ODBC Driver][Informix]Incorrect password or user [email protected] is not known on the database server. (SQL State: 28000; SQL Code: -951)
ORA-02063: preceding 2 lines from PRUEBA_SEH
As you can see i'm using heterogeneus services to connect to a informix database. ALTIADM is a valid user for that database, i don't send my ip address 192.168.0.62, but the error says "[email protected] is not known in the database server". how can i solve it?????

Right places to ask this question are
Heterogeneous Connectivity
Warehouse Builder

How to Create Public database link in oracle 9i?

Friends,
OS: RHEL AS 3
DB: 9iR2
database name 1 = nubul
database name 2 = test
in the 'nubul' database server using system user.
i created a database link to connect the 'test' database
sql> create public database link test using 'test';
database link created.
then i logged in as normal user....
sql> select count(*) from employee@test
Error at line 1:
ORA-12154: TNS: could not resolve service name
where i am making mistake?
i gave the linkname as my remote database name.
am i have to make any entry in the tnsnames.ora?
thanks & regards

You have to remember that when you access a dblink, the database where the link is defined is acting as a client to the database to which the link points ... exactly the same as if you you were using sqlplus on the machine hosting the db where the link is defined. In other words, given:
Host 'Host-src', with database 'db-src', with a dblink 'lk_target'
Host 'host-trgt', with database 'db-trgt'
When you connect to db-src and access lk-target, db-src is now acting as a client to db-trgt. Exactly as if you had opened sqlplus on host-src and connected directly to db-trgt. So, given the above scenario
host-src$> sqlplus scott/tiger@db-src
sql> select * from emp@lk_target;when you execute that SELECT to the link, the same tns considerations are in effect as if you had
host-src$> sqlplus scott/tiger@db-trgtThe same tnsnames.ora entry, on the source machine, is required for both.

Creating a database link to SQL server

Similar Messages

Maybe you are looking for