Storing negative values in MySQL

[eluser]flaky[/eluser]
since myself am not a very good regex guy I'd use callback functions from form validation class
eg

Code:

public function is_negative_float($number){
    if((float)$number && $number < 0)
        return true;
    else{
        $this->form_validation->set_message('is_negative_float', 'Enter only negative float numbers!');
        
        return false;
    }
}