I’m going crosseyed at all the (select|fetch)(all|row|col)_(array|hash)(ref)? methods in my code ... I have been fighting with an increasingly uncomfortable feeling of programming by coincidence because I can never tell ... what data structure ... my code will return. It’s killing my productivity because I’ve lost my confidence ...

If you're willing to mingle SQL with your perl, and don't mind source filters, perhaps SQL::Preproc would relieve your crosseyed productivity issues ? In most instances, you just write the SQL, inserting whatever Perl variable(s) you need to read from/write to as placeholders. No more "picking the right API call".