private function convertColumnsToRawFields(array $columns) {
        $columnMaps = $this->getModelsMetaData()->getColumnMap($this);
        foreach($columns as $key => $value) {
            if(!array_key_exists($value, $columnMaps)) {
                //Look up in the changed values
                $index = array_search($value, $columnMaps);
                if($index === false) {
                    throw new \InvalidArgumentException('Invalid Column, could not find: ' . $value);
                } else {
                    $columns[$key] = $index;
                }
            }
        }
        return $columns;
    }