You need Oracle Client Software for connecting to a database.
(More information on client-server
Installing Oracle Client
a. Downloading Oracle Client
First, you have to download client software. The client is free to
download from Oracle's website. http://www.oracle.com/technetwork/indexes/downloads/index.html
Under database section, click the database link.
In this page, choose your windows platform and client version.
Then click "see all"
In this download page, select the option box at top to accept the
license agreement and then click the client zip file.
Oracle will ask for your username and password. Register at
Oracle.com 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
2. Choose the type of client you want. (More
information on client types)
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)
4. Installer will perform prerequisite checks. If
checking fails, fulfill the necessary prerequisites and then re-run
5. If all goes well, you will see the summary
page showing the details. Click "Finish" button to start
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
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
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
ORACLE_HOME_NAME => The name that was given to this home by
ORACLE_HOME_KEY => The location of registry key for this Oracle
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
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
Client version 22.214.171.124 is installed in my machine. I've
downloaded the client setup files for version 126.96.36.199.
A small note: Version 188.8.131.52 is a major release and
available for public download. However, version 184.108.40.206 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.
I'll choose the new install option and install the client to
a new home following the same steps as described above in this
The installation is completed and now there are two clients in the
machine. OracleClient11g_home1 (version 220.127.116.11) and
OracleClient11g_home2 (version 18.104.22.168).
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
Uninstalling Oracle Client
1. Go to Start => All Programs => Oracle -
<Oracle Home Name> => Oracle Installation Products =>
2. 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.
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
4. Now the client is completely removed.