fix

db/StoredProcedures.sql

@@ -1038,6 +1038,10 @@ BEGIN
     DECLARE semID, checker INT; 
     SET semID = GetCurSemesterID();   
 
+	IF NOT (Grade > 0) THEN
+		RETURN -1;
+	END IF; 
+
     SELECT departments.ID
     INTO checker
     FROM `departments`
@@ -1058,6 +1062,7 @@ BEGIN
 	END IF;
 
 
+
 	INSERT INTO `disciplines` 	(	disciplines.AuthorID, 
 									disciplines.Grade, 
 									disciplines.SubjectID,