php - Unable to fix: "Fatal error: Call to a member function prepare() on a non-object.." -

i'm getting error , have no idea how fix it... in beginning had additionally error (same line) "db" unknown, able fix using correct syntax "$this->db..."

fatal error: call member function prepare() on non-object in c:\xampp\htdocs\gaestebuch\guestbook1.php on line 17

line 17:

$stmt = $this->db->prepare($query);

the refered code following:

include_once("datenbank.php");
class guestbook {

  public $db;    public function getentries(){       $result = false;       $query = 'select * guestbook order id desc';             $stmt = $this->db->prepare($query); //error in line (17)                                           $stmt->execute();                                                          $stmt->bind_result($id, $name, $message, $time, $date, $ip);                   while($stmt->fetch())   {                                                      $result[] = array('message' => $message,                               'name' => $name,                               'id' => $id,                               'date' => $date,                               'time' => $time);               }               $stmt->close();                                                            return $result;    }    } 

the database-connection, included in beginning looks this:

        $db = new mysqli('localhost', 'root', '', 'guestbook');          if (mysqli_connect_errno()) {             printf("verbindung fehlgeschlagen: %s\n",mysqli_connect_error());             exit();         }  

i hope can me fixing (hopefully easy peasy) error.

you have class:

class guestbook {     public $db; 

you never give $db property value, when do

$this->db->prepare($query); 

you're doing

null->prepare($query); 

give $db value in class constructor (or make sure it's passed class somehow, either way..) , you'll fine.

the

$db = new mysqli('localhost', 'root', '', 'guestbook'); 

in database connection has no relation $db variable in class unless pass class or make database-initialization happen within class.