perl -MDumpvalue -e 'my $dumper=new Dumpvalue; %hash=eval qq(return (key1,value1,key2,value2)); $dumper->dumpValue(\%hash)'

##</code><code>##

use Dumpvalue;
use DBI;

my $dumper = new Dumpvalue;
my $mysql = new DBI(...);
my $mysql->conect();
my $hash_string = $mysql->do('select .. from table');

%hash=eval $hash_string; 
$dumper->dumpValue(\%hash)