Everything you need about Oracle

You need Oracle Client Software for connecting to a database. (More information on client-server architecture)

Installing Oracle Client

a. Downloading Oracle Client

First, you have to download client software. The client is free to download from Oracle's website.

Under database section, click the database link.

Oracle Download Page
In this page, choose your windows platform and client version. Then click "see all"

Oracle Database Download Page 
In this download page, select the option box at top to accept the license agreement and then click the client zip file.
Oracle Client Download Page
Oracle will ask for your username and password. Register at if you haven't already done yet. Having an Oracle account is free.

b. Installing the Client

1. Unzip the installation files to your hard disk and run setup.exe. Your user should have administrator privileges.

Oracle Client Installation Step 1

2. Choose the type of client you want. (More information on client types)

Oracle Client Installation Step 2

3. Choose a path for Oracle Base and Oracle Home. Like database software, client software also have an Oracle Home and Oracle Base. (More information on Oracle Home and Oracle Base)

Oracle Client Installation Step 3

4. Installer will perform prerequisite checks. If checking fails, fulfill the necessary prerequisites and then re-run this step.

Oracle Client Installation Step 4

5. If all goes well, you will see the summary page showing the details. Click "Finish" button to start installation process.

Oracle Client Installation Step 5

6. After the installation is over, click the "exit" button at the final window to quit installer.

How to Find the Location of Previously Installed Clients

If you are new to a client machine, you may wonder where the previously installed clients reside. You can use registry entries to locate installed clients.

a. Run regedit

b. Navigate to "HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\" key. The "inst_loc" entry under this key shows the location of central oracle inventory.  Under this folder (the icon of keys is a folder) there is a key for each installed client. The naming format of the key is "KEY_<OracleHomeName>".

Every Oracle home is given a unique name. You do not set this name, Oracle automatically names the homes. Before 11g, you could name Oracle Homes yourself during installation.

c. For example the client we've just installed is named "OraClient11g_home1". The name of the key for this home is "HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\KEY_OraClient11g_home1". There are a couple of entries worth noting under this key

NLS_LANG => This is the National Language Support for this client. This specifies the default language,territory and character set for the client. NLS_LANG can also be specified using an environment variable. The settings specified in the environment variable overrides the one in the registry entry.

ORACLE_HOME => This entry shows the path of Oracle home.

ORACLE_HOME_NAME => The name that was given to this home by Oracle.

ORACLE_HOME_KEY => The location of registry key for this Oracle home.

Upgrading an Oracle Client

If you upgrade an Oracle Client the former client will be uninstalled and the new version will be installed into the same Oracle Home.

However this is not mandatory. You don't have to upgrade a client. You can install the new client into a new home.

When you want to use a newer client, just download the client and install it into another home as described above.

It is possible to run multiple clients in one machine. Oracle will give a name for this new home. You don't have to uninstall former clients. The latest client installed in a machine is used as a default because its path is listed before other clients in the PATH environment variable.


Client version is installed in my machine. I've downloaded the client setup files for version

A small note: Version is a major release and available for public download. However, version is released as a part of patch set. Patch sets are distributed through metalink. You have to have an active software update and support license to be able to download patch sets.

When I run the setup file for the new version Oracle asks me if I want a fresh install or an upgrade.

Oracle Client Upgrade 
I'll choose the new install option and install the client to a new home following the same steps as described above in this article.

The installation is completed and now there are two clients in the machine. OracleClient11g_home1 (version and OracleClient11g_home2 (version

Oracle Multiple Client Registry

This image is a snapshot of registry keys under Oracle. You can see the two clients that coexist in the same computer. Oracle has the ability to contain multiple clients in one station. It is even possible to run 32 bit and 64 bit clients together on a 64 bit machine.

Uninstalling Oracle Client

1. Go to Start => All Programs => Oracle - <Oracle Home Name> => Oracle Installation Products => Universal Installer

Oracle Client UnInstallation Step 1

Click "Deinstall Products ...".
Expand the Oracle Home you want to deinstall.
Select the Oracle Client listed under it.
Click "Remove ...".
Oracle will ask you to confirm operation. Click Yes.

Oracle Client UnInstallation Step 2

3. Now the client is uninstalled but the Oracle home still exists as an empty home. There is still a registry key for the client. To completely remove the Oracle Home, check the "Show Empty Homes" box. The empty home should be listed. Then select the empty home, click "Remove .." and complete the procedure.

Oracle Client UnInstallation Step 3

4. Now the client is completely removed.

Oracle Client UnInstallation Step 4

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Posted by at 05:57
Tags :
client , installation , oracle home , uninstall , upgrade
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