Installing the Oracle Client on Windows 7: Written by Joe Braun 8/2010 Windows 7 and 32-bit vs. 64-bit Issues

Prior to Windows 7, almost all operating systems and applications were 32-bit. With the release of Windows 7 and Office 2010, 64-bit applications and drivers are slowly becoming the norm. Important notes:

• 
  If your computer is running Windows XP, the operating system is almost certainly 32-bit and all of your applications are 32-bit. You will need to use 32-bit ODBC drivers for database connectivity.
  
• 
  If your computer is running Windows 7, the operating system is most likely 64-bit, but it can run 32-bit and 64-bit applications. This determines which ODBC driver(s) you will need for database connectivity. Microsoft Office 2007 (and older) is 32-bit and you will need to use 32-bit ODBC drivers. Microsoft Office 2010 comes in both 32-bit and 64-bit flavors (64-bit preferred for new installs) and will require the appropriate ODBC drivers.
  

On 64-bit Windows 7, there are two separate ODBC administrators: one for 64-bit drivers (easily found in “Administrative Tools”) and one for 32-bit drivers (hidden from an average user’s view). Now that Office 2010 is 64-bit, hopefully the need to run the 32-bit administrator will be less and less as the majority of our database applications will be 64-bit in the future.

• 
  64-bit ODBC Administrator:
  c:\windows\system32\odbcad32.exe -- This is the 64-bit ODBC Administrator program that is visible in the Control Panel -> Administrative Tools. (Note that this is 64-bit even though it is in the “system32” folder with a name of “odbcad32.exe”)
  

• 
  32-bit ODBC Administrator:
   c:\windows\SysWOW64\odbcad32.exe -- This is the 32-bit ODBC Administrator program that is hidden. Until most of our applications are 64-bit, this ODBC Administrator is more useful than its 64-bit sibling.
  

• 
  The Oracle 11.2 Client is the first officially supported Oracle client for Windows 7. While the Oracle 10 Instant Client was our preferred client for many years, it is buggy and has problems on 64-bit Windows 7. It is recommended to install the full 11.2 client on workstations.
  
• 
  It is possible to install both the 32-bit and 64-bit Oracle clients on a single computer, but they are separate installs that must be run one after the other.
  

1. 
   Determine which version of Oracle you need: 32-bit or 64-bit.
   Oracle11_2client-64bit or Oracle11_2client-32bit and run setup.exe.
   A DOS window will flash for a few moments, then the installer will appear.
   
2. 
   In the "Oracle Universal Installer: Welcome" screen, click on [Next].
   
3. 
   Select Installation Type: Choose “Administrator” to guarantee that you get all of the necessary components and utilities. (Note: You could choose “custom” if you knew what specific components you need.)
   
4. 
   Specify Home Details: For consistency, choose the following:
   Oracle Base: C:\oracle
   Software Location: C:\oracle\Client11_2_64bit (or 32bit)
   
5. 
   Click [Finish] to begin the install. Click [Close] to shut down the installer when it’s complete.
   
   POST INSTALL:
   
6. 
   Copy the UM-approved connection files tnsnames.ora and sqlnet.ora to c:\apps\oracle\InstantClient11_2_64bit\network\admin. Note: The tnsnames.ora file is a simple text file that Oracle uses to resolve MAIS server names into IP addresses.
   
7. 
   Run the appropriate ODBC Administrator (see above). Click on the [System DSN] tab, then click [Add…] and in the next screen, select the “Oracle in OraClient11g_home1” driver and click [Finish]. (Note: Name may be different if you have installed multiple Oracle clients on the same computer.)
   
8. 
   Create an entry for “GL_PO”:
   Data Source Name: GL_PO
   TNS Service Name: Choose GL_PO off of this list.

   Click [Test Connection]. If you don’t have a MAIS Oracle login, type in gibberish for the user name and password and if you get an “invalid username/password” error, that means that you are successfully connecting to Oracle! Save your DNS entry.

   
   
9. 
   As a further connectivity test, you could create a dummy Access database and attempt to link to an ODBC database. Choose the “GL_PO” entry that you created above. You should be prompted to login and asked which table(s) you want to link to. If you are able to link to a table and view the actual data, the Oracle client and ODBC connectors are working successfully!