private function fields($records, $insert = false) {
        $fields = array();
        
        foreach($records as $field => $value) {
            if($insert === true) {
                $fields[] = sprintf("`%s`", SafeString::makeSafe($field));
                $this->prepare[] = '?';
            }
            else{
                $fields[] = sprintf("`%s` = ?", SafeString::makeSafe($field));
            }
            $this->values[] = $value;
        }
        return implode(', ', $fields);
    }