FIX: converting 'null' to null for deleting absence in exam table #286

~dev_rating/application/classes/Model/Rating.php

@@ -258,6 +258,10 @@ class Model_Rating extends Model
     }
 
     public static function SetExamPeriodOptionSQL($recordBookID, $submoduleID, $option) {
+        // Для удаления неявки или автомата можно сделать так:
+        //if ($option === 'null') {
+        //    $option = '';
+        //}
         $sql = 'SELECT * FROM Discipline_SetExamPeriodOption(:recordBook, :submodule, :option) as "Num"';
         $dbAnswer = DB::query(Database::SELECT, $sql)
             ->parameters([