Need idea, for additional fields.

[misterx]

I have field "File", it receive file and saving it, decode fileinfo in json for saving in DB. When loading from DB, json becomes object.

Now i need additional fields, aka "attributes", in this object, not a additional field in DB, example "author", for save it in JSON. I think, create field "author" as "String" field from field "File" with attribute "in_db = false", with specific name. Sample

class Model_Test{
    public static function initialize($meta)
    {
        $fields = array(
            'attachment' => Jelly::field('file');
        );
        $meta->fields($fields);
    }
}

Field 'attachment' must create self, and additional field '__attachment_author':

'__attachment_author' = Jelly::field('string', array('in_db'=>false));

When i upload file.

$_FILES['attachment'] = [upload file array]; 
$_POST['__attachment_author'] = 'Upload master'; 
$m = Jelly::factory('test');
$m->set($_FILES+$_POST);
$m->save();

So, in field 'attachment' i get the value from additional field '__attachment_author' , and set it to result JSON, in method 'save';

But in this case i have a 2 problems:

1. When loading data from DB, i can't set value to additional field, because setter in Jelly_Field don't have current model instance.
2. When i change additional field ('__attachment_author'), i need resave object, but field 'attachment' is not changed, and mehod 'save' in 'attachment' field don't called.

Maybe it's wrong way?