package db_dave;
use strict;
use DBI;
use vars qw/ @ISA /;
@ISA = qw/DBI/;

sub new
{
    my $class = shift;
    my $dbh = DBI->connect('dbi:Oracle:foo', 'foo', 'foo', { RaiseError => 1 })
        || die "Cant' connect: $DBI::errstr";
    my $data = {
        _dbh => $dbh
    };
    bless $data, $class;
    return $data;
}

sub runsql_returnString_NEW
{
    my ($self, $q, $err) = @_;
    my $dbh = $self->{ _dbh };
    my $sth = $dbh->prepare($q);
    $sth->execute || &error($q, $err); # <- why do you have a regular function in an OO module?

    my $returnstring;
    while (my @array = $sth->fetchrow) {
        # ?? You're overwriting this every time :(
        # I can't tell what type of data structure you want
        $returnstring = $array[0];
    }

    $sth->finish;
    return $returnstring;

}