diff --git a/course/edit_form.php b/course/edit_form.php
index a305da4ced3..373e149baff 100644
--- a/course/edit_form.php
+++ b/course/edit_form.php
@@ -328,19 +328,23 @@ class course_edit_form extends moodleform {
 
 /// perform some extra moodle validation
     function validation($data, $files) {
-        global $DB, $CFG;
+        global $DB;
 
         $errors = parent::validation($data, $files);
-        if ($foundcourses = $DB->get_records('course', array('shortname'=>$data['shortname']))) {
-            if (!empty($data['id'])) {
-                unset($foundcourses[$data['id']]);
+
+        // Add field validation check for duplicate shortname.
+        if ($course = $DB->get_record('course', array('shortname' => $data['shortname']), '*', IGNORE_MULTIPLE)) {
+            if (empty($data['id']) || $course->id != $data['id']) {
+                $errors['shortname'] = get_string('shortnametaken', '', $course->fullname);
             }
-            if (!empty($foundcourses)) {
-                foreach ($foundcourses as $foundcourse) {
-                    $foundcoursenames[] = $foundcourse->fullname;
+        }
+
+        // Add field validation check for duplicate idnumber.
+        if (!empty($data['idnumber']) && (empty($data['id']) || $this->course->idnumber != $data['idnumber'])) {
+            if ($course = $DB->get_record('course', array('idnumber' => $data['idnumber']), '*', IGNORE_MULTIPLE)) {
+                if (empty($data['id']) || $course->id != $data['id']) {
+                    $errors['idnumber'] = get_string('courseidnumbertaken', 'error', $course->fullname);
                 }
-                $foundcoursenamestring = implode(',', $foundcoursenames);
-                $errors['shortname']= get_string('shortnametaken', '', $foundcoursenamestring);
             }
         }
 
diff --git a/course/lib.php b/course/lib.php
index 1796bae10da..bdb14936dcb 100644
--- a/course/lib.php
+++ b/course/lib.php
@@ -3962,6 +3962,20 @@ function update_course($data, $editoroptions = NULL) {
         $data = file_postupdate_standard_editor($data, 'summary', $editoroptions, $context, 'course', 'summary', 0);
     }
 
+    // Check we don't have a duplicate shortname.
+    if (!empty($data->shortname) && $oldcourse->shortname != $data->shortname) {
+        if ($DB->record_exists('course', array('shortname' => $data->shortname))) {
+            throw new moodle_exception('shortnametaken', '', '', $data->shortname);
+        }
+    }
+
+    // Check we don't have a duplicate idnumber.
+    if (!empty($data->idnumber) && $oldcourse->idnumber != $data->idnumber) {
+        if ($DB->record_exists('course', array('idnumber' => $data->idnumber))) {
+            throw new moodle_exception('courseidnumbertaken', '', '', $data->idnumber);
+        }
+    }
+
     if (!isset($data->category) or empty($data->category)) {
         // prevent nulls and 0 in category field
         unset($data->category);
diff --git a/course/tests/courselib_test.php b/course/tests/courselib_test.php
index f8f185fd07f..9d167bfa060 100644
--- a/course/tests/courselib_test.php
+++ b/course/tests/courselib_test.php
@@ -97,6 +97,53 @@ class courselib_testcase extends advanced_testcase {
         $this->assertEquals(range(0, $course->numsections + 1), $sectionscreated);
     }
 
+    public function test_update_course() {
+        global $DB;
+
+        $this->resetAfterTest();
+
+        $defaultcategory = $DB->get_field_select('course_categories', 'MIN(id)', 'parent = 0');
+
+        $course = new stdClass();
+        $course->fullname = 'Apu loves Unit Təsts';
+        $course->shortname = 'test1';
+        $course->idnumber = '1';
+        $course->summary = 'Awesome!';
+        $course->summaryformat = FORMAT_PLAIN;
+        $course->format = 'topics';
+        $course->newsitems = 0;
+        $course->numsections = 5;
+        $course->category = $defaultcategory;
+
+        $created = create_course($course);
+        // Ensure the checks only work on idnumber/shortname that are not already ours.
+        update_course($created);
+
+        $course->shortname = 'test2';
+        $course->idnumber = '2';
+
+        $created2 = create_course($course);
+
+        // Test duplicate idnumber.
+        $created2->idnumber = '1';
+        try {
+            update_course($created2);
+            $this->fail('Expected exception when trying to update a course with duplicate idnumber');
+        } catch (moodle_exception $e) {
+            $this->assertEquals(get_string('courseidnumbertaken', 'error', $created2->idnumber), $e->getMessage());
+        }
+
+        // Test duplicate shortname.
+        $created2->idnumber = '2';
+        $created2->shortname = 'test1';
+        try {
+            update_course($created2);
+            $this->fail('Expected exception when trying to update a course with a duplicate shortname');
+        } catch (moodle_exception $e) {
+            $this->assertEquals(get_string('shortnametaken', 'error', $created2->shortname), $e->getMessage());
+        }
+    }
+
     public function test_course_add_cm_to_section() {
         global $DB;
         $this->resetAfterTest(true);