I am trying to write a class that will allow me to add a member to my users database change tehir password log them in and out, i am using the PEAR DB class to connect to my database, i am getting this error when i run the script, i am trying to login:

Fatal error: Call to a member function on a non-object in /home/nanothre/public_html/classes/member.class.php on line 22

My member class is here:(I have put a comment next to line 22)

PHP Code:

class member {

    var $db;
    var $databaseTable;
    var $username;
    var $password;
    var $result;
    
    function login($username, $password){
        if(!get_magic_quotes_gpc()){
            $password = addslashes($password);
            $username = addslashes($username);
        }
        $password = md5($password);
        $sql = "SELECT id, username, password FROM $databaseTable WHERE username = '$username' AND password = '$password'";
        $this->result = $db->query($sql); //<<<<<<<<<<<<<<<<LINE 22
        if (DB::isError ($result)){
            die('There was an error while processing the query: '. $result->getMessage());
        }
        if($result->numRows() > 0){
            $row = $result->fetchrow(DB_FETCHMODE_ASSOC);
            $_SESSION['id'] = $row['id'];
            $_SESSION['username'] = $row['username'];
            $_SESSION['password'] = $row['password'];
            print_r($_SESSION);
        } else {
            return false;
        }
        $result->free();
    }
    
    function logout(){
        session_destroy();
    }    
    
    function newMember($password, $username, $email){
        if(!get_magic_quotes_gpc()){
            $password = addslashes($password);
            $username = addslashes($username);
            $email = addslashes($email);
        }
        $sql = "INSERT INTO $databaseTable(username, email, password) VALUES('$username','$email','$password')";
        $result = $db->query($sql);
        if (DB::isError ($result)){
            die('There was an error while processing the query: '. $result->getMessage());
        }
    }
} 


After the username and password have been submitted this is what is called by the script:

PHP Code:

    $member = new member;
    $member->databaseTable = 'test_users';
    $member->db = $db;
    $member->login($_POST['username'], $_POST['password']); 


Can anyone explain what is wrong?

You're trying to use a $db object that doesn't exist. You need to reference class member variables with the $this keyword.

PHP Code:

$this->result = $this->db->query($sql); 


Which means you also have a couple other lines to correct (working with $result and another with $db in the newMember() method).

thanks alot chroder, ill try that now then, i'm pretty new to OOP

How come i dont have to use the $this referance with this line:

PHP Code:

$password = md5($password); 


$this only refers to the class member methods (functions) and properties (variables). Since $password was passed to the function, it became a variable in the local scope to the function.

Check out variable scope and the section on the $this pointer in classes and objects.