Ask PHP master! Questions about the application of MongoDB

Ask PHP master! Questions about MongoDB Application!
MongoDB a library has a collection of IDs, where the original data is Db.ids.insert ({' Name ': ' User ', ' ID ': 0})
I want to implement a self-growing ID by the following method. The code is as follows:

PHP Code

  
   public static function Autoid ($name, $db) {    $update = array (' $inc ' =>array (' id ' =>1));    $query = Array (' name ' = = $name);    $command = Array (' findandmodify ' = ' IDs ', ' update ' = $update, ' query ' + $query, ' new ' =>true);    echo Json_encode ($command). "
";//Output 1    $id = $db->command ($command);    echo Json_encode ($id). "
";//Output 2    return $id [' value '] [' ID '];}

Calling this method does not implement the target. The output is:
Output 1: {"findandmodify": "IDs", "Update": {"$inc": {"id": 1}}, "query": {"name": "User"}, "new": true}
Output 2: {"errmsg": "No such cmd", "Bad cmd": {"findandmodify": "IDs", "Update": {"$inc": {"id": 1}}, "query": {"name": "User"}, " New ": true}," OK ": 0}

Excuse me, what's going on here? Will it be the MONGO version?

------Solution--------------------
Didn't use MongoDB. I don't know what the situation is.
------Solution--------------------
What is your version of MongoDB?
Http://www.mongodb.org/display/DOCS/findAndModify+Command

See document is v1.3 above only support

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