Take Programs --> Net8 Configuration Assistant --> add --> local net8 service name configuration --> name of the service(say xyz.world) --> port #(1521,default) --> test --> finish

Thats will reflect in your tnsnames.ora

You can use that service name(xyz) which you hjave created thru net8 configuration assistant as connect_string for database connection.

Example: sqlplus system/manager@xyz

I don't know what you are trying to do, this is what you supposed to do to create a service name.