my ($curmag,$curiss,$curart)=();
my (%mag,%iss,%art);
while (my $d=fetchrow_hashref) {

  if (($curiss eq $$d{issue_number) &&
      ($curmag eq $$d{mag_name)) {
     push(@iss,{article_name=>$$d{article_name}});

  } else { # new issue and/or magazine
    $mag{issue_loop}=\@iss if (defined($curiss));
    @iss=[{article_name=>$$d{article_name}}]; # not sure if that assigns a new ref. to array. Check FIRST!
    $curiss=$$d{issue_number}
  }
  if ($curmag ne $$d{mag_name}) {
     push(@data,\%mag) if defined($curmag);
     %mag={}; # see if that assigns new ref, as above
     $mag{mag_name}=$$d{mag_name};
     push(@data,\%mag) if defined($curmag);
     $curmag=$$d{mag_name};
  }
}