change discipline: students annihilation

db/StoredProcedures.sql

@@ -1718,6 +1718,20 @@ BEGIN
 		RETURN -1;
 	END IF;
 
+	SELECT disciplines.Grade 
+	INTO checker
+	FROM `disciplines`
+	WHERE disciplines.ID = DisciplineID
+	LIMIT 1;
+
+	IF checker != Grade THEN
+		DELETE FROM `disciplines_groups`
+		WHERE disciplines_groups.DisciplineID = DisciplineID;
+
+		DELETE FROM `disciplines_students`
+		WHERE disciplines_students.DisciplineID = DisciplineID;
+	END IF;
+
 
 	UPDATE `disciplines`
 	SET 	disciplines.ExamType = ExamType,