Settingup linked server between SQL Server and Oracle


In most cases, our installation and configuration processes do not change from 32-bit to 64-bit: setting up logins, creating SQL Agent jobs; nothing inherently different there.  Inconsistencies do exist however.  Take for example linked servers – more specifically linked servers to Oracle databases.  In 32-bit environments we simply install the Oracle client software, create the linked server, add remote logins and move on to the next project.  In the 64-bit world the process is slightly more difficult – and in the case of one critical step it impacts any existing users on the instance!

Process Creating Oracle Linked Server on a 64-bit SQL Instance:

  • Install Oracle 10g Release 2 64-bit client software (available from Oracle website)
  • Install Oracle 10g Release 2 64-bit ODAC software (available from Oracle website)
  • Restart SQL services
  • Configure OraOLEDB.Oracle provider
  • Create linked server
  • Add remote logins for linked server

The complete process is presented below:

Step One:  Installation of the Oracle 10g Release 2 64-bit client software

I will leave it up to you to secure the software by either download from their site or media available via any licensing agreements you may have with Oracle.  The important steps are outlined below.  You only need the barest install of the client.  Simply go ahead and select the InstantClient option from the opening dialog form and click Next.

The following screens simply require you to click Next when enabled.  These are in place to present the internal checks and summaries of work to be completed once you accept the install parameters.  Proceed through the screens, click Install, and then Finish once the installation is complete.

Step Two:  Installation Oracle 10g Release 2 64-bit ODAC software

Once you have an installed 64-bit Oracle Home you can proceed with installing the ODAC drivers for a 64-bit environment.  The OraOLEDB.Oracle driver installed in this step is what you need to set up your linked server.  You’ll find the setup.exe for this installation located in the unzipped Install folder.  I strongly suggest you review your previous installation of the client software via selecting the Installed Products button.  You want to verify that you have a valid 64-bit Oracle Home that you’ll be installing against during this process.  We would not be DBAs if we were not overly cautious.  It’s quite Darwinian:  the brash and risky don’t last long as Database Administrators.

If you accepted the defaults during the client installation, your “Installed Products” Inventory should appear as follows.  If so, then close the dialog and click Next to continue.  If not, then I suggest you revisit your installation of the client software, possibly de-installing and performing all steps presented previously once again.

We will be installing the OraOLEDB.Oracle driver that is included in the Oracle Data Access Components option .  Select Next to continue.

Using the drop-down box provided, select the existing Oracle Home you just verified was created as a part of your 64-bit Oracle client installation.  The Path will automatically change accordingly.  Continue by clicking Next.

You will be presented with the following sub-components.  I’ve selected all three (you never know when these items may be useful and they are extremely lightweight) though you only really need to install the first two items.

If you do decide to install the Oracle Services for Microsoft Transaction Server component, you’ll be prompted for the port number to use.  The default is 2030.

Click Next and you’ll be presented with the familiar summary screen, listing all components to be installed.  Review, make changes if necessary and then click Install.  Once completed we can move back to familiar territory:  SQL Server Management Studio.

After Completion Of Installation We need to Change Couple of things in TNSNAMES.ora

Edit TNSNAMES.ora

<install directory>Product10.2.0ClientnetworkADMINTNSNAMES.ora (i.e. C:Oracle\Product\10.2.0\Client\network\ADMIN\TNSNAMES.ora)

There is a very specific format to the network configuration file. Here is an example to get you started (just copy & paste multiple entries if necessary):

DMDEV =

(DESCRIPTION =

(ADDRESS_LIST =

(ADDRESS = (PROTOCOL = TCP)(HOST = SERVERNAME)(PORT = 1521))

)

(CONNECT_DATA =

(SERVICE_NAME = FRIENDLYNAME)

)

)

There are a couple of things you need to change:

  • HOST = SERVERNAME. The SERVERNAME should be changed to reflect the actual address or hostname of the target system.
  • SERVICE_NAME = FRIENDLYNAME. FRIENDLYNAME is the name by which you refer to this actual connection.

 

Step Three:  Restart SQL Service

This is the most unfortunate step in the entire process.  This is usually the last thing a DBA wants to do.  It is the option of last resort whenever there is an issue on a SQL Server instance.  However, it is necessary in this case, so be sure to follow your corporate procedures for downtime notifications and process.  That being said, let’s move past this horrid step!

Step Four:  Configure OraOLEDB.Oracle provider

I confess.  I was not aware of this process existing until I had to do this the first time.  In Object Explorer, navigate down the tree of the SQL instance we’ve been working with until you’re able to view the list of Providers under Linked Servers.  Select OraOLEDB.Oracle and right-click in SQL Server Management Studio.

The Provider Options dialog box appears.  Enable the “Allow inprocess” option and close the dialog.  Now ask yourself:  “Self, what did I just do?  Some Internet Guy said click this and it will work.”  Let’s take a quick look at exactly what enabling this option does for a provider.  By default, OLE DB providers are instantiated outside of the SQL Server process.  While this protects SQL from any OLE DB errors, Microsoft SQL Server requires that the OLE DB provider run in-process for handling BLOB-ish data types (text and images).

Step Five:  Create a linked server to the Oracle Database

In General  TAB :

Linked Server : A name of your choosing which you will use when querying using four-part naming conventions.

Server Type : Other Data Source

Provider: Oracle Provider for OLE DB

Product Name: “Oracle” is fine here

Data Source: This should match the Service_Name Which you defined in TNSNAMES.ora

Create a Linked Server

In Security TAB : Select Be made using this security context Option and supply the remote login and password.

And then TEST the Connection ..

Hope this helps you a lot!!

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