I'm developping an application with .net framework and i wanted to use entity framework, and oracle as data base system, so i installed oracle 10g express edition.
After that i wanted to install 64bits ODAC from here http://www.oracle.com/technetwork/database/windows/downloads/index-090165.html,
and it marked that it required the installation of oracle tools for visual studio first, i installed it from here http://www.oracle.com/technetwork/topics/dotnet/utilsoft-086879.html
Then i configured my TNS file as it indicated here http://www.tensixconsulting.com/2012/06/setting-up-an-oracle-odbc-driver-and-data-source/ ,
in the step where i should add the user DSN i found as 'Oracle in ORAClient11g_home2' and i add it , but in the configuration i didn't found the TNS name service that i named on the tns file, it doesn't appear in the selection list. So i wrote it directly, the system demanded the user ID and the password, i wrote it and i had this error
Unable to connect
[Oracle][ODBC][Ora] ORA-12154: TNS:could not resolve the connect identifier specified
and i'm sure that i entred my Id and my passowrd correctly
NB: When i was searchin the tnsnames file, i found 2 directory of client in the path 'C:\app\BAYREM\product\11.2.0' there are 'client_1' and 'client_2' i think that the first is for the oracle tools for visual studio and the second is for the 64bits ODAC
You will need to have the correct connect alias in the TNSNAMES.ORA for the Oracle home that ODBC is using. 32-bit vs 64-bit is probably helping to confuse the question of which TNSNAMES.ORA is being used.
The error you are getting says that it can't find that alias in the TNSNAMES.ORA that it is looking in.
For ODBC specific configuration questions, try the ODBC forum: ODBC