cek email dulu sebelum insert

<?php
//connect.php
$dsn  = "mysql:dbname=test";
$host = "localhost";
$user = "test";
$pass = "";
try {
    $conn = new PDO($dsn, $user, $pass);
} catch (PDOException $e) {
    echo "Koneksi ke database gagal: ".$e->getMessage();
}

//simpan.php
include 'connect.php';

if (isset($_POST)) {
    //cek dulu email udah ada atau belum di database
    $sql = 'SELECT COUNT(*) jumlah_user FROM tabel_biodata WHERE email=:email';
    $sth = $conn->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
    $sth->execute(array(':email' => $_POST[email]));
    $row = $sth->fetch(PDO::FETCH_ASSOC);
    if ( $row['jumlah_user] > 0 ) {
        //artinya email udah ada, silahkan tampilkan pesan error
    }
    else {
        //hanya insert jika email belum ada!!!
        $st = $conn->prepare('INSERT INTO tabel_biodata ( noreg, nama, email, jenis_kelamin, nm_perusahaan, alamat, tlp, no_hp, hadir, photo ) VALUES( :noreg, :nama, :email, :jenis_kelamin, :nm_perusahaan, :alamat, :tlp, :no_hp, :hadir, :photo )';
        $result = $st->execute( array(
            ':noreg'            => $_POST['noreg'],
            ':nama'             => $_POST['nama'],
            ':email'            => $_POST['email'],
            ':jenis_kelamin'    => $_POST['jenis'],
            ':nm_perusahaan'    => $_POST['nm'],
            ':alamat'           => $_POST['alamat'],
            ':tlp'              => $_POST['tlp'],
            ':no_hp'            => $_POST['no'],
            ':hadir'            => $_POST['hadir'],
            ':photo'            => $_POST['photo'],
        ) );
        //tampilkan pesan sukses atau gagal
    }
}