use strict;
use DBI;

# CREATE TABLE `t` (
#  `a` text
# ) DEFAULT CHARSET=utf8;

my $user = 'root';
my $pass = '';

my $dbh = DBI->connect(
            'DBI:mysql:test;host=localhost',
            $user,
            $pass,
            { mysql_enable_utf8 => 1 });

my $str = "before\x{1f3c4}after";

my $sth = $dbh->prepare('INSERT INTO t VALUES (?)');
$sth->execute($str);

# mysql> select a, length(a), char_length(a) from t;
# +--------+-----------+----------------+
# | a      | length(a) | char_length(a) |
# +--------+-----------+----------------+
# | before |         6 |              6 |
# +--------+-----------+----------------+
# 1 row in set (0.01 sec)