Class explanation ?

[coop]

Hi all,

 

I'm new to php but come from using Actionscript, so I understand alot of what PHP has to offer.

I'm learning php so I can use it with Flash - I'm using a friends of Ed book which is good but some things are unexplained.

 

This class is from the book and is used to connect to the database - I understand the idea of classes and how they work but could someone give a quick explanation of how this class is supposed to work, and do you think it is better to use a class for this or use seperate statments, (which I feel more comfortable using, ,cos I can understand them better. ) such as

 

$con = mysql_connect('localhost','root','root');

 

 

<?php
class Database {

  protected $host;
  protected $user;
  protected $pwd;
  protected $dbName;
  protected $flash;
  protected $dbLink;
  protected $result;
  protected $resultObj;

  function __construct($host, $user, $pwd, $dbName, $flash=1){
    $this->host = $host;
    $this->user = $user;
    $this->pwd = $pwd;
    $this->dbName = $dbName;
    $this->flash = $flash;
$this->connect();
    }

  public function connect() {
    try {
      $this->dbLink = @mysqli_connect($this->host, $this->user, $this->pwd, $this->dbName);
      if (!$this->dbLink) {
        throw new Exception ("Couldn't connect $this->user to $this->dbName");
        }
      }
    catch (Exception $e) {
      echo $this->flash ? 'error='.urlencode($e->getMessage()) : $e->getMessage();
      exit();
      }
    return $this->dbLink;
    }

  public function query($query) {
    try {
      $this->result = mysqli_query($this->dbLink, $query);
      if (!$this->result) {
        throw new Exception ('MySQL Error: ' . mysqli_error($this->dbLink));
        }
      }
    catch (Exception $e) {
      echo $this->flash ? 'error='.urlencode($e->getMessage()) : $e->getMessage();
      exit();
      }

$this->resultObj = new MyResult($this->result);
return $this->resultObj;
    }

  public function close(){
    mysqli_close($this->dbLink);
    }	
  }

class MyResult {

  protected $theResult;
  public $num_rows;
  
  function __construct($r) {
      if (is_bool($r)) {
    $this->num_rows = 0;
	}
  else {
    $this->theResult = $r;
    $this->num_rows = mysqli_num_rows($r);
	}
}
  
  function fetch_assoc() {
    $newRow = mysqli_fetch_assoc($this->theResult);
return $newRow;
}
  }
?>