scales should be (courseid, scale) unique, since it's already abused it's not possible to add a unique in db, so we add additional check in GUI. Duplicate scale, course causes mapping problems in backup/restore

grade/edit/scale/edit_form.php

@@ -81,7 +81,17 @@ class edit_scale_form extends moodleform {
 
 /// perform extra validation before submission
     function validation($data){
+        
+        global $CFG;
+        
         $errors= array();
+        
+        // we can not allow 2 scales with the same exact scale as this creates
+        // problems for backup/restore
+        $courseid = empty($data['courseid'])?0:$data['courseid'];
+        if (count_records('scale', 'courseid', $courseid, 'scale', $data['scale'])) {
+            $errors['scale'] = get_string('duplicatescale', 'grades');  
+        }  
 
         $options = explode(',', $data['scale']);
         if (count($options) < 2) {
@@ -94,8 +104,6 @@ class edit_scale_form extends moodleform {
             return $errors;
         }
     }
-
-
 }
 
 ?>

lang/en_utf8/grades.php

@@ -94,6 +94,7 @@ $string['droplow'] = 'Drop the lowest';
 $string['dropped'] = 'Dropped';
 $string['dropxlowest'] = 'Drop X Lowest';
 $string['dropxlowestwarning'] = 'Note: If you use drop x lowest the grading assumes that all items in the category have the same point value. If point values differ results will be unpredictable';
+$string['duplicatescale'] = 'Duplicate scale';
 $string['edit'] = 'Edit';
 $string['editcalculation'] = 'Edit Calculation';
 $string['editfeedback'] = 'Edit Feedback';