OOP: práce s databází v děděných třídách*

$db = new db();
$auth = new auth($db);

class auth {

	private $db;

	public function __construct(&$db) {
		$this->db = $db;
	}
}

dibi::query ("...");

dibi::activate('alfa databaze');
dibi::query(...);

dibi::select('foo, bar')->from('users')->where('foo <= %i', $max ?: 10)->orderBy('bar')->desc()->fetchAssoc('foo');

->desc()->

$sql = DBQ::InsertSQLFromArray($table, $fields_array);

$jedna = new Treti();
$dve = new Druha();
$tri = new Treti();

DB::Connect('admin')->query(...);

class myDBi{
  public myQuery($q){
    ...
  }
}
class myDB{
  private $default_instance = null;
  public static myQuery($q){
    if (!default_instance) $default_instance = new myDBi();
    self::$default_instance->myQuery($q);
  }
}

class DB {
	static $connection = Array();
	static $credentials = false;
	
	static function Connect() {
		// přihlašovací údaje
		if ( (self::$credentials === false) ) {
			if ( file_exists( ... ) ) 
				self::$credentials = unserialize(file_get_contents( ... ));
			else
				throw new DatabaseException('Database connection configuration file is missing.');
		}

		switch (func_num_args()) {
		case 0:
			$connection_name = 'default';
			break;
		case 1:
			$name = func_get_arg(0);
			if ( isset(self::$credentials[$name]) ) {
				$connection_name = $name;
			} else {
				throw new DatabaseException('Invalid name of database connection');
			}
			break;
		default:
			throw new DatabaseException('Invalid number of arguments for connection.');
		} 
		
		if ( isset(self::$connection[$connection_name]) && is_object(self::$connection[$connection_name]) ) {
			return self::$connection[$connection_name];
		} else {
			self::$connection[$connection_name] = new mysqli( ... );
			if (mysqli_connect_error()) {
				self::$connection[$connection_name] = false;
				throw new DatabaseException('Database connection failed.');

			}
			return self::$connection[$connection_name];
		}

	}

}

DB::Connect()->query(...); // default
DB::Connect('admin')->query(...); // jiné než default