* Perform a full text search query and return a result set.
*
* @param string $term Raw search term
- * @return SqlSearchResultSet
+ * @return SqlSearchResultSet|null
*/
abstract protected function doSearchTextInDB( $term );
* Perform a title-only search query and return a result set.
*
* @param string $term Raw search term
- * @return SqlSearchResultSet
+ * @return SqlSearchResultSet|null
*/
abstract protected function doSearchTitleInDB( $term );