Mongo - 排序循环

Question

Ok i am using mongo db and have a repeating region on my page:

try {

    $connection = new Mongo();
    $database   = $connection->selectDB($selectDB);
    $collection = $database->selectCollection($selectCollection);

} catch(MongoConnectionException $e) {
    die("Failed to connect to database ".$e->getMessage());
}

$cursor = $collection->find();

while ($cursor->hasNext()): $document = $cursor->getNext(); 


                        echo $document['fieldName']."<br/>";
                        echo $document['fieldType']."<br/>";
                        echo $document['fieldLength']."<br/>";
                        echo $document['user_id']."<br/>";
                        echo $document['order']."<br/>";
                        echo "<hr/>";

 endwhile;

this works fine but what i am trying to do now is sort by user_id. I have tried this:

 try {

    $connection = new Mongo();
    $database   = $connection->selectDB($selectDB);
    $collection = $database->selectCollection($selectCollection);

} catch(MongoConnectionException $e) {
    die("Failed to connect to database ".$e->getMessage());
}

$cursor = $collection->find().sort({user_id: -1});

while ($cursor->hasNext()): $document = $cursor->getNext(); 


                        echo $document['fieldName']."<br/>";
                        echo $document['fieldType']."<br/>";
                        echo $document['fieldLength']."<br/>";
                        echo $document['user_id']."<br/>";
                        echo $document['order']."<br/>";
                        echo "<hr/>";

 endwhile;

The line i altered is the: $cursor = $collection->find().sort({user_id: -1});

i am getting php error when id o this. Can someone show me the proper syntex to get this array to sort.

I have also tried:

$cursor = $collection->find()->sort({user_id: -1});

and 

 $cursor = $collection->find();
 $cursor = $cursor.sort({user_id: -1});

Any help would be appreciated. thanks.

answer found*

$cursor = $collection->find();
$cursor->sort(array('user_id' => 1));

Answer 1

I think this is a PHP syntax error:

$collection->find().sort({user_id: -1})

is invalid PHP. In PHP, the dot operator (".") is used to concatenate strings, not to access object members. For that, use the arrow operator ("->"). Additionally, "{user_id: -1}" is not correct syntax for an associative array in PHP. For that, use "array("user_id" => -1)".

This gives us:

$collection->find()->sort(array("user_id" => -1))

which I believe should work.