Linked Server setup with Oracle

Linked Server Setup with Oracle in SQL Server:

Suppose you want to access data from oracle or other database products using T-SQL via SQL server database Engine then you need to configure Linked Server.

You can learn about Linked Server from MSDN .

Here I show an example to setup linked server with oracle.

First install oracle client on machine where you want to configure linked server.

Go to [Oracle Client Installation Directory]\product\11.2.0\]dbhome_1\NETWORK\ADMIN

Open tnsnames.ora file.(It is Network configuration file for oracle)

Add TNS setting in this file as Example here

PROD =

  (DESCRIPTION =

    (ADDRESS_LIST =

      (ADDRESS =

        (PROTOCOL = TCP)

        (HOST = 192.168.10.10)

        (PORT = 1521)

      )

    )

    (CONNECT_DATA =

      (SERVICE_NAME = PROD)

    )

  )

See more details of tnsnames.ora file.

Test oracle connection:

Open cmd

Enter SQLPLUS

Enter USERNAME:  username@PROD

Enter PASSWORD: password

Type any select query to confirm connection.

Now come on SQL Server.

In object explorer, Expand Server Object tree Node and see linked server

Right click on linked server and select New Linked Server and Enter required information

Select Security option and enter credentials

Click Ok.

If all things are right linked server configured now.

Now Test your linked server.

Run query as

SELECT a.*

FROM OPENQUERY(linkedservername,'SELECT *from oracledatabasename.table_or_view') a;

Basic Syntax of OPENQUERY

OPENQUERY ( linked_server ,'query' )

Using OpenQuery you can INSERT,DELETE , UPDATE,DELETE.

Example Select Query:

SELECT a.*

FROM OPENQUERY(PRODNEW,'SELECT *from Apps.customer_details') a;

Example INSERT Query:

INSERT OPENQUERY (PRODNEW, ‘SELECT ID,name FROM Apps.customer_details’)

VALUES ('C121’,’Uma Shankar');

Example UPDATE Query:

UPDATE OPENQUERY (PRODNEW, 'SELECT name FROM Apps.customer_details WHERE id = ''C121''')

SET name = 'Uma Shankar Patel';

Example DELETE Query:

DELETE OPENQUERY (PRODNEW, 'SELECT ID FROM Apps.customer_details WHERE ID = ''C121''');

This query fetch data from oracle via SQL server database engine.

It is the little about linked server.I have learned this when my client require to develop a web site that fetch data from sql server but customer data of client comes from oracle.

• Insert data from Oracle to SQL Server over linked server 

INSERT INTO sqldatabasename.dbo.tablename

(

col1,

col2,

col3

)

SELECT a.*

FROM OPENQUERY(likedservaername,'SELECT

col1,

col2,

col3

from oracletablename') a;

• Insert data from SQL server to Oracle over linked server 

INSERT INTO OPENQUERY(linkedservername,'select

col1,

col2,

col3                   

from oracletablename')

   SELECT

   col1,

   col2,

   col3

  FROM sqldatabase.dbo.tablename;

• Delete data from Oracle over linked server

DELETE OPENQUERY (linkedserver, 'Select *from oracetablename');   

In the same way you can create linked server with oracle,mysql and other rdbms and can use above sample query as required. 

• Update oracle table from SQL Server

  
  
  UPDATE u

  SET u.oraclefieldname = ‘value’

  from

  openquery(likedservername,'select *from oracletable') as u

  where u.hdr_id = @rid

codeproject