PHP: Object Oriented Everything - Please review!

I haven't coded PHP in a while, so I was wondering how I could expand my knowledge of OOP through a hands on practice. What I've done is tried to make everything an object; I've not got so far yet, but if any PHP gurus could criticize my code and give me some tips for improvement I'd be grateful

lib/database.php:

<?php

class database {

	public static $connection;
	
	public function __construct($db_host = DB_HOST, $db_name = DB_NAME, $db_username = DB_USERNAME, $db_password = DB_PASSWORD) {
		self::$connection = mysql_connect($db_host.':'.$db_port, $db_username, $db_password) or errors::write_error('MySQL Connection failure');
		mysql_select_db($db_name, self::$connection) or errors::write_error('MySQL Database selection failure');
	}

}

class query {
	
	public $sql;
	public $success;
	public $resource;

	public function __construct($sql, $autoprefix = true, $autoexecute = true) {
		$this->sql = $sql;
		if($autoprefix === true) $this->prefix();
		if($autoexecute === true) $this->execute();
	}

	public function prefix() {
		$this->sql = str_replace("#", DB_TBLPREFIX, $this->sql);
	}
	
	public function execute() {
		$this->resource = mysql_query($this->sql, database::$connection) or errors::write_error(mysql_error(database::$connection));
		$this->success = (is_resource($this->resource)) ? true : false;
	}
	
}

class insert_query extends query {
	
	protected $table;
	protected $fields;
	protected $values;
	const RAW_DATA = 1;
	
	public function __construct($table, $fields, $values) {
		if(count($fields) == count($values)) {
			$this->table = $table;
			$this->fields = implode(',', $fields);
			foreach($values as $k => $value) {
				if(is_array($value)) {
					if(count($value) == 2 && $value[0] == self::RAW_DATA) {
						$this->values .= $value[1].',';
					}
				}
				else {
					$this->values .= '\''.$value.'\',';
				}
			}
			$this->values = substr($this->values, 0, (strlen($this->values) - 1));
			return parent::__construct('INSERT INTO `'.$this->table.'` ('.$this->fields.') VALUES ('.$this->values.')');
		}
		else {
			errors::write_error('Field count did not match value count');
			return false;
		}
	}
		
}



?>

Code (markup):

index.php (example usage):

<pre>
<?php

include '../config.php';
include 'lib/errors.php';
include 'lib/database.php';

$database = new database();

$query = new query("SELECT hello FROM #_world");

while($names = mysql_fetch_array($query->resource)) {
	echo $names['hello']."\n";
}

$insert = new insert_query('#_world', array('hello'), array('Will'));

?></pre>

Code (markup):