prosesinput

<? php
# MEMBUAT KONEKSI DATABASE
    // Definisi Variabel Untuk Koneksi
    $host = "localhost"; // Nama Host
    $user = "root"; // Nama user
    $pass = ""; // Password
    $db = "absenn"; // Nama Database
    // Melakukan Koneksi Ke Database MYSQL
    $mysql = new mysqli($host, $user, $pass, $db);
    /* check koneksi */
    if (mysqli_connect_errno()) {
        printf("Connect failed: %s\n", mysqli_connect_error());
        exit();
    }
    if(isset($_POST['simpan'])) {
    $id_karyawan=$_POST['id_karyawan']
    $nama=$_POST['nama'];
    $alamat=$_POST['alamat'];
    $no_telp=$_POST['no_telp'];
    $username=$_POST['username'];
    $password=$_POST['password'];
    //cek id
    $cek = mysqli_num_rows(mysqli_query($query, "SELECT * FROM tb_karyawan WHERE id_karyawan='$id_karyawan'"));
    if ($cek > 0){
        echo'gagal';
    }else {
    mysqli_num_rows($query, "INSERT INTO tb_barang(id_barang, nama_barang, harga_satuan, quantity)
                  VALUES ('$id_barang', '$nama_barang', '$harga_satuan', '$quantity')");
        echo'sukses';
        }
    }
    ?>