I recently upgraded my oracle client to 10g (10.2.0.1.0).
Now when I try to connect to a legacy 8.0 database, I get
ORA-03134: Connections to this server version are no longer supported.
Is there any workaround for this problem, or do I have to install two clients on my local machine?
Yes, you can connect to an Oracle 8i database with the 10g client, but the 8i Database requires the 8.1.7.3 patchset, which you can get from Oracle's Metalink support site (requires login).
Here's an Oracle forum post with the details.
selecthome.bat
file to switch between your installed clients.
For example, before connecting to 8i, you'd run:
C:\Oracle\Client1_8i\bin\selecthome.bat
or this to use your Oracle 10g client:
C:\Oracle\Client2_10g\bin\selecthome.bat