Accessing variables in super class

Anon

Hi,

I have written a class (DBConnection.obj) that connects to a database. Inside this class, I have declared a couple of variables which determine the hostname, userID, and password to use to connect to the database. I have also written a class (User.obj) which extends the DBConnection class.

The problem is that when I instantiate a User.obj class and then call DBConnection's openConnection method, for some reason the variables are not recognized and I receive the following error:

Warning: MySQL Connection Failed: Access denied for user: username@localhost' (Using password: NO) in /home/origin/www/classes/db/DBConnection.obj on line 16

The code is as follows:

//DBCOnnection object
class DBConnection
{

var $hostname = "localhost";
var $username = "origin";
var $password = "CNuyMNhX";
var $dbName = "originxcreative_com";
var $numRows = 0;

  @MYSQL_SELECT_DB($this->dbName) or die( "Unable to select database.  Reason: " . mysql_error());

}

//User object
class User extends DBConnection
{
....<snip>
}

//test.phtml
<?php

$UserBean = new User();
$UserBean -> openConnection();

The strange thing is that if I instantiate a DBConnection object and then directly call its openConnection() method, the connection works. Is there something I'm doing wrong with the variable declarations?

Thanks,
Phil

mithril

Everything looks mostly fine, but you should move the variable set calls into the constructor for class DBConnection (it doesn't look they're in there no, but that may just be the code snippet).

Please note, in the current implemenation of OO in PHP, classes do not automatically call their parent's constructor. Thus, you need to place a call to the DBConnection constructor from within the User constructor. Clear as mud? Hopefully the following modification to your example will illustrate my point🙂

N.B. Note that I'm creating the User object by reference..... you should always do this unless you're creating and object you intend to pass aroud as a global.

<?php
    //DBCOnnection object
  class DBConnection {

    var $hostname;
    var $username;
    var $password;
    var $dbName;
    var $numRows;

    function DBConnection($hostname="",$username="",$password="",$dbName="")
    {
        // set the connection variables
      $hostname == "" ? $this->hostname = "localhost" : $this->hostname = $hostname;
      $username == "" ? $this->username = "origin" : $this->username = $username;
      $password == "" ? $this->password = "CNuyMNhX" : $this->password = $password;
      $dbName == "" ? $this->dbName = "originxcreative_com" : $this->dbName = $dbName;
      $this->numRows = 0;
    }

    function openConnection()
    {
        //Opens a connection to the MySQL database
      MYSQL_CONNECT($this->hostname, $this->username, $this->password) or die("Unable to connect to database. Reason: " . mysql_error());
      @MYSQL_SELECT_DB($this->dbName) or die( "Unable to select database. Reason: " . mysql_error());
    }
  }

    //User object
  class User extends DBConnection {

    function User() {
      $this->DbConnection();
    }
  }

  $UserBean = &new User();
  $UserBean->openConnection();
?>

HTH.

-geoff