package DB;
use strict;
use DBI;

sub new {
    my $class = shift;
    my $dsn   = shift; 
    my $dbh = DBI->connect($dsn, "", "",{RaiseError=>1, AutoCommit=>1});
    return bless { _dbh => $dbh }, $class;
}

sub dbh {
    my $self = shift;
    return $self->{_dbh};
}

sub createtb {
    my ($self, $form, $tabler) = @_;
    my $dbh = $self->dbh();
    # ...
}

# --- Test.pl

use strict;
use DB;
use SQL::Abstract;

my $sql = SQL::Abstract->new();
my $db  = DB->new("dbi:SQLite:dbname=test.db");
# ...
$db->createtb($form2,$popsamp);
# ...