Script PHP-Membuat inputan mahasiswa

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<body>
<p><strong>Entry Mahasiswa</strong></p>
<form id="form1" name="form1" method="post" action="entrymhs.php">
  <table width="397" border="0">
    <tr>
      <td width="70">NIM</td>
      <td width="317"><label for="nim"></label>
      <input type="text" name="nim" id="nim" /></td>
    </tr>
    <tr>
      <td>Nama</td>
      <td><input type="text" name="nama" id="nama" /></td>
    </tr>
    <tr>
      <td>Prodi</td>
      <td><select name="prodi" id="prodi">
        <option value="MI-D3">Manajemen Informatika - D3</option>
        <option value="KA-D3">Komputer Akuntansi - D3</option>
        <option value="TI-D3">Teknik Informatika - D3</option>
        <option value="SI-S1">Sistem Informasi - S1</option>
        <option value="TI-S1">Teknik Informatika - S1</option>
      </select></td>
    </tr>
    <tr>
      <td>&nbsp;</td>
      <td><input type="submit" name="aksi" id="button" value="Simpan" />
      <input type="reset" value="Reset" /></td>
    </tr>
  </table>
</form>
<p>
<?php
//cek apakah user menekan tombol simpan
if (isset($_POST['aksi']) && $_POST['aksi']=="Simpan"){
$nim = $_POST['nim'];
$nama = $_POST['nama'];
$prodi = $_POST['prodi'];
//cek nilai masing2 inputan
if ( !empty($nim) && !empty($nama) && !empty($prodi)){
//proses simpan ke database
$cn = mysql_connect("localhost","root","");
$db = mysql_select_db("akademik", $cn);
$sql = "INSERT INTO mahasiswa(nim,nama,prodi) VALUES('$nim', '$nama', '$prodi')";
mysql_query($sql, $cn);
if ( mysql_affected_rows($cn)>0 )
$pesan = "Proses input data mahasiswa berhasil";
else
$pesan = "Proses input data mahasiswa gagal";
}else{
$pesan = "Input data tidak valid!";
}
echo $pesan;
}
?>
</p>
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