UPDATE
Untuk mengubah data yang sudah ada, silahkan ketika code dibawah ini didalam file index.php :
<?php
require 'function.php';
$mahasiswa = query("SELECT * FROM mahasiswa");
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Admin Data Mahasiswa</title>
</head>
<body>
<h1>Daftar Mahasiswa</h1>
<a href="tambah.php">Tambah Data</a>
<br><br>
<table border="1" cellpadding="10" cellspacing="0">
<tr>
<th>No.</th>
<th>Aksi</th>
<th>Photo</th>
<th>Nama</th>
<th>NPM</th>
<th>Jurusan</th>
<th>Email</th>
</tr>
<?php $i = 1; ?>
<?php foreach ($mahasiswa as $row) : ?>
<tr>
<td> <?= $i; ?> </td>
<td>
<a href="ubah.php?id=<?php echo $row["id"]; ?>">Ubah</a> |
<a href="hapus.php?id=<?php echo $row["id"]; ?>" onclick="return confirm('Yakin Ingin Menghapus Data'); ">Hapus</a>
</td>
<td><img src="img/<?php echo $row["gambar"] ?>" width="50"></td>
<td><?php echo $row["nama"] ?></td>
<td><?php echo $row["npm"] ?></td>
<td><?php echo $row["jurusan"] ?></td>
<td><?php echo $row["email"] ?></td>
</tr>
<?php $i++; ?>
<?php endforeach; ?>
</table>
</body>
</html>