mongodb在PHP中检索Mongo集合的字段 - mongodb Retrieve fields of Mongo collection in PHP

mongodb Retrieve fields of Mongo collection in PHP

我尝试在光标上使用fields()方法：

<?php
$mongo  = new Mongo("mongodb://localhost");
print_r($mongo);
$db = $mongo->test;
// access collection
$collection = $db->test;
// execute query
// retrieve all documents
print_r($test);
$cursor = $collection->find();
print_r($cursor);
$fields = $cursor->fields(array("summary" => true));
print_r($fields);

输出为：

Mongo Object ( [connected] => 1 [status] => [server:protected] => [persistent:protected] => )
MongoCursor Object ( )
MongoCursor Object ( )

看起来驱动程序和连接正常，但我无法检索字段的不同摘要。

假设我们可以访问名为db的mongodb数据库，将从MyCollection检索数据，并使用mongodb ''Driver''Manager：

  $manager = new MongoDB'Driver'Manager( $DB_CONNECTION_STRING );

然后，在这种情况下，我们通过name检索数据，并限制2文档，并希望获得仅字段name、age和address等投影选项可用于指定应使用0排除和1包括返回哪些字段：

  $filter = ['name' => 'John'];
  $options = [ 'projection' => ['_id' => 0, 'name' => 1, 'age' => 1, 'address' => 1], 'limit' => 2 ];
  $query = new MongoDB'Driver'Query($filter, $options);
  $manager->executeQuery('db.MyCollection', $query);

如果我们需要获取所有列，那么我们只需省略投影选项，如下所示：

  $filter = ['name' => 'daniel'];
  $options = [];
  $query = new MongoDB'Driver'Query($filter, $options);
  $manager->executeQuery('db.MyCollection', $query);

 const HOST = 'localhost';
 const PORT = 27017;
 const DBNAME = 'test';
 const COLLECTION = 'test';
 $connectionString = sprintf('mongodb://%s:%d', HOST, PORT);
 try {
        $connection = new Mongo($connectionString);
        $database = $connection->selectDB(DBNAME);
 } catch (MongoConnectionException $e) {
        throw $e;
}
$collection = $database->selectCollection(COLLECTION);
try{
        $query = array();
        $specifyKey = array("summary" => true);
        $cursor = $collection->find($query , $specifyKey);
}catch(MongoException $e) {
        die('Failed to find One data '.$e->getMessage());
}catch (MongoCursorException $e) {
    echo "error message: ".$e->getMessage()."'n";
    echo "error code: ".$e->getCode()."'n";
}
while ($cursor->hasNext()){
    $nextCursor = $cursor->getNext(); 
    //process next cursor
}

在$cursor变量之后，尝试foreach。它遍历光标结果。

foreach($cursor as $document) {  
 var_dump($document);  
}