public static function getInstancia() { if (!self::$instancia) { self::$instancia = new BaseDeDatos(); } return self::$instancia; }
public function __construct($host = null, $usuario = null, $contrasena = null, $bd = null) { $this->host = $host; $this->usuario = $usuario; $this->contrasena = $contrasena; $this->bd = $bd; $this->conexion(); self::$instancia = $this; }