how to hide oracle instance name within dbi code??

[Linda Ding]

We have a requirement here that we can't hard code any oracle database 
instance name for security reasons. Is there any way we can pass the 
connection string (for example, the oracle tnsname alias), or put the 
instance name in a configuration file and somehow pass the information 
from the configuration to the DBI code,  so that the public won't see 
the actual instance name in the code???? I know we can do that in many 
other languages, but, can we do that using DBI for oracle???

use strict;
use DBI;

my $dbh = DBI->connect( 'dbi:Oracle:orcl',
                      'jeffrey',
                      'jeffspassword',
                    );


 
Thanks a lot for any input.

Linda