index_save.php

<?php
session_start();
//print_r ($_POST);
$error=[];
$username='root';
$password='';
$db='form';
$conn=new mysqli('localhost',$username,$password,$db);
if($conn->connect_error){
    die("Connection cannot be established". $conn->connect_error);
}

if (isset($_POST['name'],$_POST['nim'],$_POST['kontak'],$_POST['mail'],$_POST['fakultas'],$_POST['prodi'])){
    $fields=[
        'name'=>$_POST['name'],
        'nim'=>$_POST['nim'],
        'mail'=>$_POST['mail'],
        'kontak'=>$_POST['kontak'],
        'fakultas'=>$_POST['fakultas'],
        'prodi'=>$_POST['prodi']
        ];

        foreach($fields as $items=>$values){
            if (empty($values)){
                $error[]='The '.$items.' field is required !';
            }
        }
            $sql="INSERT INTO formtable (nama,nim,mail,kontak,fakultas,prodi) VALUES ('".$fields["name"]."','".$fields["nim"]."','".$fields["mail"]."','".$fields["kontak"]."','".$fields["fakultas"]."','".$fields["prodi"]."')";
                if ($conn->query($sql) === TRUE) {
                            echo "New record created successfully";
                        } else {
                            echo "Error: " . $sql . "<br>" . $conn->error;
                        }

} else {
    echo $error[]='Something went wrong .';
}
$_SESSION['error']=$error;
//header('Location: index.php');

?>