Classes para conexão com banco de dados e Modelo para manipulação em PHP

database.php

<?php

// Debug
function pr ($array) {
	echo '<pre>';
	print_r($array); 
	echo '</pre>';
}

/** 
 * Database configuration
 */ 
class DATABASE_CONFIG 
{ 
	public static $config = array(
		'driver' => 'mysql',
		'host' => 'localhost',
		'login' => 'root',
		'password' => '',
		'database' => 'teste',
		'encoding' => 'utf8',
	);
}

/** 
 * Object
 */ 
class Object { }

/** 
 * Database
 */ 
class Database extends Object 
{ 
	private $con;
	private static $driver = null;
	
	public function __construct () { 
		$config = DATABASE_CONFIG::$config;
		switch ($config['driver'])
		{
			case 'mysql' : 
				$this->driver = new MySQL;
				$this->con = $this->driver->connect(
					$config['host'], 
					$config['login'], 
					$config['password'], 
					$config['database']
				);
				break;
		}
		if (isset($config['encoding'])) {
			$this->driver->query(sprintf('SET NAMES `%s`', $config['encoding']));
		}
	} 
	
	public static function open () {
		if (!self::$driver) {
			self::$driver = new DataBase;
		}
		return self::$driver;
	}
	
	public function query ($sql) {
		return $this->driver->query($sql);
	}
	
	public function fetch_assoc ($query) {
		return $this->driver->fetch_assoc($query);
	}
	
	
}

/** 
 * Drivers
 */ 
abstract class Drivers extends Object 
{ 
	abstract function connect ($host, $username, $password, $database);
	abstract function query ($query);
	abstract function fetch_assoc ($query);
}

/** 
 * MySQL
 */ 
class MySQL extends Drivers 
{ 
	public function connect ($host, $username, $password, $database) { 
		$con = mysql_connect($host, $username, $password);
		mysql_select_db($database);
		return $con;
	} 
	
	public function query ($sql) {
		return mysql_query($sql);
	}
	
	public function fetch_assoc ($query) {
		return mysql_fetch_assoc($query);
	}
}

/** 
 * Model
 */ 
class Model 
{ 
	private $database;
	protected $table;
	protected $fields = '*';
	protected $cond;
	
	public function __construct () { 
		$this->database = Database::open();
		$this->setTable();
	}
	
	private function setTable () {
		if (!$this->table) {
			$this->table = strtolower(get_class($this));
		}
	}
	
	public function all ($conditions = null) {
		$sql = sprintf('SELECT %s FROM `%s` %s', $this->fields, $this->table, $conditions);
		$query = $this->database->query($sql);
		
		$data = array();
		while ($line = $this->database->fetch_assoc($query)) {
			$data[] = $line;
		}
		return $data;
	}
	
	public function __call ($function, $args) {
		if (preg_match('/^(findAllBy)(.*)/', $function, $matches)) {
			$field = $matches[2];
			$field = preg_replace('/([A-Z])/', '_\\0', $field);
			$field = strtolower(substr($field, 1));
			
			$cond = sprintf('WHERE `%s` = "%s"', $field, $args[0]);
			return $this->all($cond);
		}
	}
	
}

/** 
 * Artigos
 */ 
class Artigos extends Model { }

// Examples
$artigos = new Artigos;
$data = $artigos->all();
$data2 = $artigos->findAllByIdCategoria(2);

pr($data);
pr($data2);

?>