in reply to Unable to connect to Oracle 19c
There's multiple issues:
Put use strict; at the top of all of your Perl code.
In this case, it will highlight many lines that need to start with my.
POD directives should be surrounded by blank lines.
That's not an absolute requirement, but is needed in some cases, so it's best to do it everywhere.
See "perlpod: Hints for Writing Pod".
See "DBD::Oracle - connect()".
It shows multiple formats, none of which match what you've coded.