如何更新MongoDb文档中的内部数组

I'm trying to add php array to MongoDB document

{
    "_id" : ObjectId("51b043e1d07a4e9e06000004"),
    "comments" : {
        "count" : 0,
        "array" : []
    }
}

array:

$array = array(
       "user_id" => $comment["user_id"],
       "text" => $comment["text"]
);

Using this:

$this->database->Collection->update(array("_id" => new MongoId($comment["object_id"])), array('$push' => $array);

However, it doesn't seem to work and I can't find why. I don't know MongoDb well yet... Thanks

The value of the $push needs to be another PHP array with a key that names the array field to update and a value that's the element to add. So in this case it would be:

$this->database->Collection->update(
    array("_id" => new MongoId($comment["object_id"])), 
    array('$push' => array("comments.array" => $array)));