I'm using DBD::ODBC module. When I execute my connecting string, I kept getting this error:
Data source name not found and no default driver specified.

I tried to use the DBD::ODBC's connecting without DSN:
my $DSN = 'driver={Oracle ODBC Driver};Server=10.2.3.0:1521;database=ORADB;uid=oraadmin;pwd=oraadminpassword;';
my $dbh = DBI->connect("dbi:ODBC:$DSN") or die "$DBI::errstr\n";

But the same error message occurs. I think I might have put the wrong driver= because I cannot find an example for oracle database so I just used the syntax for mysql:
http://search.cpan.org/~mjevans/DBD-ODBC-1.22/FAQ#How_do_I_connect_without_DSN