OOP mysql class

[marcin_koss]

Hello everybody.

 

I am starting learning OO PHP and after reading many articles about it I am trying to start writing my first class which would be a class that handles mysql connections and performs queries. Below is the code I wrote so far but I'm already stuck with this error:

"Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in D:\www\mysql_connect_oop.php on line 36"

 

I would appreciete if somebody could take a look a the code and tell me where could be the problem.

 

<?php

// class mysql_con

class mysql_con{

 

var $name;

var $pass;

var $host;

var $db;

var $query;

var $result;

 

function __construct($n, $p, $h, $d) {

$this->name = $n;

$this->pass = $p;

$this->host = $h;

$this->db = $d;

}

function connect() {

mysql_connect($this->host, $this->name, $this->pass);

mysql_select_db($this->db);

}

function query($q) {

$this->query = $q;

}

function result() {

$this->result = mysql_query($this->query) or trigger_error("Query: $this->query\n<br />MySQL Error: " . mysql_error());

}

 

}

 

// script that opens connection and performs query

 

$db = new mysql_con('root','martek123','localhost','world');

$db->query('SELECT name FROM city WHERE name = "bialystok"');

 

while ($row = mysql_fetch_array($db->result)) {

echo $row['name'];

}

 

?>

[premiso]

You never call the connect function before you run the query. Either put it in the constructor to call it automatically on the class instantiation or call it before you call the query function.