The hashref is passed to a sub. {} notation isn't quite so effective.

Using $${ref} is a matter of style. I like $$ for straight refs, -> for obj. refs

Forgot entirely about the 'x' operator. Much cleaner than map.

$sth -- again, style preference. I like to know what's going on. query, insert, etc...

main() keeps me from using globals. I write all of my code with pragma strict, so using subs for all of the code requires 'my' prefixes.
sub dbConnect and getData were used to facilate looping. While not a golfer, I do try to write concise code.
Forgive me for having the hubris to write perl code that facilates pre-existing mySql code. This is perlmonks. Not mySqlmonks.