Message: No fields or rules have been added for validation

and related on this question how can i get all validation in same error message seted by fvalidation and that seted by form automaticaly depends on database fields.

I would put an if statement around your validation:

$fields = $object->getValidationFields();
if ($fields) {
    $validator = new fValidation();
    $validator->addRequiredFields($fields);
    $validator->validate();
}

I'm not positive what you are asking in your second question, but I'll try to answer it. If you need to combine validation sources, you can use ->validate(TRUE), merge the validation arrays and then pass them to fValidationException.

$validator = new fValidation();
$validator->addRequiredFields($fields);

$messages = array_merge(
    $validator->validate(TRUE),
    $active_record->validate(TRUE)
);

if ($messages) {
    throw new fValidationException('The following problems were found:', $messages);
}