Where I work, we have an older database which is Oracle 7.3. There are some web application running on a Windows 2008 R2 server in IIS 7 created using ASP.NET which connect to this database with the Oracle 8i client. That worked fine until I needed to create a new web application (ASP.NET) which connects to Oracle 10g R2 using the ODP.NET ODAC 11g. The new program worked correctly with no issues using the new client. The problem is now the old applications will not work and some times it is intermittently switching back and forth where the web application using the 8i client work and the new one does not and vice versa.
When the old application stops working I get ORA-12154: TNS:could not resolve the connect identifier specified
Is there a way to implicently tell the web applications which Oracle client to use? Any help would be greatly appreciated.