create then save a default empty row
$one = Model::factory('foo')->create();
$one->save();

raises:
Warning: array_fill() : Number of elements must be positive in idiorm.php on line 592

fix

line 591 idiorm.php:
protected function _create_placeholders($number_of_placeholders) {
if ($number_of_placeholders) {
return join(", ", array_fill(0, $number_of_placeholders, "?"));
}
return "";
}