Question

Resulting from a MapReduce, I have a MongoDb collection that has the following structure:

{ "_id" : { "id" : NumberLong(1), "date" : "04-26-2012" }, "value" : { "count" : 100 } }

In my controller I am doing the following to return an array to display the results:

$mongoDb         = $mongo->selectDatabase($dbname);        
$mongoCollection = $mongoDb->selectCollection($collname);
$qb              = $mongoCollection->createQueryBuilder(); 
$qb              = $qb->find();        
$resultCursor    = $qb->getQuery()->execute();
                                  ->limit(10);
$resultArray     = $resultCursor  ->toArray();

However, I get an exception: “Notice: Array to string conversion in vendor/doctrine-mongodb/lib/Doctrine/MongoDB/Cursor.php line 154”

Below is line 154 of Cursor.php. Does MongoCursor::key not handle “_id” as an Array?

/** @proxy */
public function key()
{
    return $this->mongoCursor->key();
}

Answer 1

key() always returns a string (see http://php.net/manual/en/class.iterator.php), so it’s generating that notice trying to convert an array into string form. It is only a notice, though, it should still work.

The easiest way around this is probably just not to call toArray() on the cursor: iterate through it instead (foreach $resultCursor as $value) ...).