my @COLUMNS;
push ( @COLUMNS, $_)for ( 1 .. $last_column );
my $column_list = map { print "field$_, " } @COLUMNS;
my $placeholders = { print "?, " for ( 1 .. $last_column ) };

my $insert_data = $dbh->prepare(<<SQL);
insert into $filename ($column_list) values ($placeholders)
SQL

foreach (<DATAFILE>)
{
    my (@ROW) = split /,/, $_;
    my $row_list = map { print "\'$_\', " } @ROW;
    $insert_data->execute($row_list);
}