Setting Up ODBC Connection for Oracle 10g
After installing Oracle 10g version on the Windows 64-bit version machine and trying to set the ODBC connection you see the error: ORA-12154: TNS:Could not resolve the connect identifier specified
By default Oracle 10g version will be installed on Windows 64-bit version in the directory like that “C:\Program Files (x86)\…”. And Oracle 10g doesn't allow to have parenthesis in the installation directory. That is why it is not able to establish a connection with the source database and shows an error.
There are 2 ways of resolving such a case.
Copy the Program
You can copy the installed program to some other directory with out parenthesis. For example “C:\Program Files\…”. After that you will need to change the previous Oracle installation directory to the actual BIN directory value in the environment variable PATH.
Also you will need to check if there are environment variables “tns_admin” and “oracle_home” on your machine, then you will need to specify actual values in these variables also.
Only after correcting the environment variables and restarting your working environment you will be able to successfully connect to your source database.
Update your Oracle
The other way is to update your Oracle 10g version to 11g version.
After the installation process is finished you need to check whether environment variables use correct paths to the 11g version. By default during installation process such variables should be rewritten to the correct values, but sometimes Oracle may leave them as they are. And in that case we need to check them and set to appropriate values.