$client = new \MongoClient(MONGO_DB);
$users = $client->users;
$last_views = $users->createCollection('last_views', 1, 1024, 10);
$last_views->ensureIndex(array("user_id" => 1, "warecode" => 1), array("unique" => 1));
$uviews = new \stdClass();
$uviews->user_id = $this->user_id;
$uviews->warecode = $this->warecode;
$uviews->lasttime = new \MongoTimestamp();
$res = $users->last_views->update(
$uviews,
array('$set' => array('lasttime' => new \MongoTimestamp())),
array('upsert' => true)
);