Class variable awareness

[mijokijo]

Let say you have this code:

<?php

class Db 
{
	private $database_server;
	private $username;
	private $password;
	private $database_name;
	public $connection;

	__construct($db_server, $db_name)
	{
		$database_server = $db_server;
		$database_name = $db_name;
	}

	function dbconnect()
	{
		if ($database_server == 'postgresql')
		{
			$connection = pg_connect("dbname=$database_name");
		} elseif ($database_server == '') {
			die('No database server specified');
		}			
	}
}

?>

Now let's say that I have another class, class XYZ, that have code to run different queries based on what $database_server is. So if I type $db = new Db('postgresql', 'monkeys'), then I'd like class XYZ to run a query using postgresql functions rather than mysql functions. How would I make class XYZ aware of the value of $database_name? Would making it a public variable be safe?

[konsu]

introduce a member variable in to the class XYZ and set it appropriately to indicate which database engine to use.

[mrhappiness]

I wlays thought in php5 you still have to use $this?

$this->database_server = $db_server;

for example