如何使用PHP代码从mongodb中名为group的集合中获取数据

这是我从mongodb中的集合获取数据的PHP代码：

$m = new Mongo('localhost');
$m->connect();
$db = $m->mydb;
$collection = $db->fields_current;
$cursor = $collection->find();
foreach ($cursor as $obj) {
    echo $obj["title"] . "\n";
}

该代码适用于当前的集合

字段
。但是，我有这样一个集合
fields\u current.node
，其中
node
是集合的命名组。如何从命名组获取数据

编辑：

按照PeterM的回答，我得到了一个空的MongoCursor对象。这是我的新代码：

$m = new Mongo('localhost');
$m->connect();
$db = $m->mydb;
$collection = $db->fields_current;
$query = array(array('group_name' => 'node', 'type' => 'content-type'), array('title' => 1)); // SELECT title FROM fields_current WHERE group_name = 'node' AND type = 'content-type'
$cursor = $collection->find($query);
foreach ($cursor as $obj) {
    echo $obj["title"] . "\n";
}

更多细节：我正在使用Drupal，
node
指的是“node”表，
type
指的是“node type”。集合名称为
fields\u current.node
，记录结构如下：

array (
  '_id' => new MongoInt32(37),
  '_type' => 'node',
  '_bundle' => 'content-type',
  '_revision_id' => new MongoInt32(37),
  'nid' => new MongoInt32(37),
  'vid' => new MongoInt32(37),
  'type' => 'content-type',
  'language' => 'und',
  'title' => 'title',
  'uid' => new MongoInt32(1),
  'status' => new MongoInt32(1),
  'created' => new MongoInt32(1342065549),
  'changed' => new MongoInt32(1342065549),
  'comment' => new MongoInt32(1),
  'promote' => new MongoInt32(0),
  'sticky' => new MongoInt32(0),
  'tnid' => new MongoInt32(0),
  'translate' => new MongoInt32(0),
  'field_cutom_field' => 
  array (
    'value' => 'foobar',
  ),
)

有关更多示例，请参见
，因为它的Drupal不需要指定数据库名称，就像编写MySql查询时一样。还有一个不同的函数用于获取集合对象

// Suppose you have a collection called 'collection_name', then you can get its object using this code.
$collection = mongodb_collection('collection_name');

// Suppose you have a collection called 'collection_name.group', where 'group' is the named group of this collection, then you can get its object using this code.
$collection = mongodb_collection('collection_name', 'group');

// Rest of the operations will be same.
$cursor = $collection->find(array('type' => 'content-type'));
foreach ($cursor as $obj) {
  ....
  // Do your work...
  ....
}

但它返回一个空的MongoCursor对象。如何从那里取回田地。我查阅了文档，看起来我遗漏了什么。我是mongodb新手。查询是要查找的第一个参数，而字段是第二个参数。你做了一个数组。它应该是
$collection->find（$query，$fields）所以它应该是
$query=array（'group_name'=>'节点'，'type'=>'内容类型'）（注意：您没有字段组\u名称，是否应该是\u类型？）和
$fields=array（'title'）
// Suppose you have a collection called 'collection_name', then you can get its object using this code.
$collection = mongodb_collection('collection_name');

// Suppose you have a collection called 'collection_name.group', where 'group' is the named group of this collection, then you can get its object using this code.
$collection = mongodb_collection('collection_name', 'group');

// Rest of the operations will be same.
$cursor = $collection->find(array('type' => 'content-type'));
foreach ($cursor as $obj) {
  ....
  // Do your work...
  ....
}