diff --git a/lib/cube/event.js b/lib/cube/event.js
index 4825904e..8ee16b84 100644
--- a/lib/cube/event.js
+++ b/lib/cube/event.js
@@ -33,7 +33,15 @@ exports.putter = function(db) {
         type = request.type;
 
     // Validate the date and type.
-    if (!type_re.test(type)) return callback({error: "invalid type"}), -1;
+    var keys = type.split('.');
+    keys.forEach(function(t) {
+      if (!type_re.test(t)) {
+        return callback({error: "invalid type"}), -1;
+      }
+    });
+    var type = keys[0];
+    var key = keys.slice(1).join('.');
+    
     if (isNaN(time)) return callback({error: "invalid time"}), -1;
 
     // If an id is specified, promote it to Mongo's primary key.
@@ -41,7 +49,7 @@ exports.putter = function(db) {
     if ("id" in request) event._id = request.id;
 
     // If this is a known event type, save immediately.
-    if (type in knownByType) return save(type, event);
+    if (type in knownByType) return save(type, event, key);
 
     // If someone is already creating the event collection for this new type,
     // then append this event to the queue for later save.
@@ -77,7 +85,7 @@ exports.putter = function(db) {
       // Save any pending events to the new collection.
       function saveEvents() {
         knownByType[type] = true;
-        eventsToSaveByType[type].forEach(function(event) { save(type, event); });
+        eventsToSaveByType[type].forEach(function(event) { save(type, event, key); });
         delete eventsToSaveByType[type];
       }
     });
@@ -91,8 +99,14 @@ exports.putter = function(db) {
   // delay between saving the event and invalidating the metrics reduces the
   // likelihood of a race condition between when the events are read by the
   // evaluator and when the newly-computed metrics are saved.
-  function save(type, event) {
-    collection(type).events.save(event, handle);
+  function save(type, event, key) {
+    if (event._id !== undefined) {
+      var updater = {t: event.t};
+      updater[key !== '' ? 'd.' + key : 'd'] = event.d;
+      collection(type).events.update({_id: event._id}, {$set: updater}, {safe: true, upsert: true}, handle);
+    } else {
+      collection(type).events.save(event, handle);
+    }
     queueInvalidation(type, event);
   }