protected function _validate($column, $model, $data, $onlyIfAvailable) {
        if ($onlyIfAvailable && !array_key_exists($column, $data)) {
            return;
        }
        $value = array_key_exists($column, $data) ? $data[$column] : null;
        $colType = $this->_getColumnType($column, $model);

        if ($colType == 'numeric') {
            $this->_validateNumber($value, $column);
            return;
        }

        $this->_validateString($value, $column);
    }