use strict;
use warnings;
use DBI;
use JSON;

my @output;
my $dbh = DBI->connect('dbi:Pg:dbname=foo','bar','baz');
my $sth = $dbh->prepare('select * from qux');
$sth->execute;

while ( my $row = $sth->fetchrow_hashref ){
    push @output, $row;
}

print objToJson( { myData => \@output } );