php stmt

<?php
//Περιέχει λειτουργίες που σχετίζονται με τη βάση
class dbfunctions {
  //Στοιχεία σύνδεσης στη βάση
  public $username = '';
  public $pass = '';
  public $host = '';
  public $db = '';
  /////////////////////

//Επιστρέφει σύνδεση στη βάση η error
  public function db_connect() {
    $dbconnection = new mysqli($this->host, $this->username, $this->pass, $this->db);
    if (!$dbconnection) {
       die("Cannot Connect to Database");
    } else {
      return $dbconnection;
    }
  } //db_connect() end

/*Εκτελει δυναμικα τα queries
Arguments: 1 = prepared query with ?, 2 = type of params e.g 's' 3 = array(query parameters)
Σε περιπτωση select query επιστρεφει τον $final_results ως multidimensional array
e.g $final_results['username'][1]*/
  public function prepared_stmt($query, $type, $params) {
    try {
     $conn = $this->db_connect();
     $stmt = $conn->prepare($query);
     if (!$conn || !$stmt) {
       throw new Exception('Connection error!');
     }
     $stmt->bind_param($type, ...$params);
     $stmt->execute();
     if ($stmt->error) {
        throw new Exception('Execution error!');
      }
     if (strpos($query, 'SELECT') !== false) {
       $results = $stmt->get_result();
       $final_results;
       while ($select_results = $results->fetch_assoc()) {
         foreach($select_results as $column=>$row_value) {
           $final_results[$column][] = $row_value;
         } //foreach end
       } //while end
       return $final_results;
     }
   } catch (Exception $e) {
       die($e->getMessage());
   }
 } //prepared_stmt() end
} //dbfunctions class end
?>