diff --git a/ceilometerclient/tests/unit/v2/test_alarms.py b/ceilometerclient/tests/unit/v2/test_alarms.py
index 4239d2f..9d3b75e 100644
--- a/ceilometerclient/tests/unit/v2/test_alarms.py
+++ b/ceilometerclient/tests/unit/v2/test_alarms.py
@@ -529,6 +529,23 @@ class AlarmTimeConstraintTest(testtools.TestCase):
         ]
         self.http_client.assert_called(*expect)
 
+    def test_update_time_constraint_no_name(self):
+        updated_constraint = {
+            'start': '0 23 * * *',
+            'duration': 500
+        }
+        kwargs = dict(time_constraints=[updated_constraint])
+        self.mgr.update(alarm_id='alarm-id', **kwargs)
+        body = copy.deepcopy(AN_ALARM)
+        body[u'time_constraints'].append({
+            'start': '0 23 * * *',
+            'duration': 500,
+        })
+        expect = [
+            'PUT', '/v2/alarms/alarm-id', body
+        ]
+        self.http_client.assert_called(*expect)
+
     def test_remove(self):
         kwargs = dict(remove_time_constraints=['cons2'])
         self.mgr.update(alarm_id='alarm-id', **kwargs)
diff --git a/ceilometerclient/v2/alarms.py b/ceilometerclient/v2/alarms.py
index 18cdbb0..a54183a 100644
--- a/ceilometerclient/v2/alarms.py
+++ b/ceilometerclient/v2/alarms.py
@@ -135,14 +135,15 @@ class AlarmManager(base.Manager):
             updated_tcs = [dict(tc) for tc in existing_tcs]
             for tc in new_tcs:
                 for i, old_tc in enumerate(updated_tcs):
-                    if old_tc['name'] == tc['name']:  # if names match, merge
+                    # if names match, merge
+                    if old_tc['name'] == tc.get('name'):
                         utils.merge_nested_dict(updated_tcs[i], tc)
                         break
                 else:
                     updated_tcs.append(tc)
         tcs_to_remove = kwargs.get('remove_time_constraints', [])
         for tc in updated_tcs:
-            if tc['name'] in tcs_to_remove:
+            if tc.get('name') in tcs_to_remove:
                 updated_tcs.remove(tc)
         return updated_tcs