I have installed Instant Client thru Instant Client option in Oracle Database 11g Release 2 Client (220.127.116.11.0) for Microsoft Windows (x64) NOT thru Instant Client package.
Then I installed the oledb from 64-bit ODAC 11.2 Release 3 (18.104.22.168.1) for Windows x64 by executing install.bat oledb c:\oracle odac.
I find the following values in registries:
under HKEY_LOCAL_MACHINE\SOFTWARE\Oracle\KEY_odac: NLS_LANG has the value AMERICAN_AMERICA.WE8MSWIN1252 OLEDB has the value c:\Oracle\oledb\mesg ORACLE_GROUP_NAME has the value Oracle - odac ORACLE_HOME has the value c:\Oracle ORACLE_HOME_NAME has the value odac
under HKEY_LOCAL_MACHINE\SOFTWARE\Oracle\KEY_OraClient11g_home1: NLS_LANG has the value AMERICAN_AMERICA.WE8MSWIN1252 ORACLE_GROUP_NAME has the value Oracle - OraClient11g_home1 ORACLE_HOME has the value C:\Oracle\product\11.2.0\client_1 ORACLE_HOME_NAME has the value OraClient11g_home1
I wonder whether I have done the installations incorrectly since some keys have different values between the 2 registries.