in reply to Advice - storing data - which structure do you recommend? (details inside)

DBI and SQL is the way to go. Here are a few links to get you started:

Mark-Jason Dominus's A Short Guide to DBI;

DBI manpage

Tricks with DBI

Programming the Perl DBI;

You can use the DBD::CSV driver to flat files (Comma Separated Value test files) if you do not have a real database available.