MONGOCOLLECTION.AGGREGATECURSOR(3)					 1					MONGOCOLLECTION.AGGREGATECURSOR(3)

MongoCollection::aggregateCursor - Execute an aggregation pipeline command and retrieve results through a cursor

SYNOPSIS

       public MongoCommandCursor MongoCollection::aggregateCursor (array  $command, [array  $options])

DESCRIPTION

	With  this  method  you can execute Aggregation Framework pipelines and retrieve the results through a cursor, instead of getting just one
       document back as you would with MongoCollection::aggregate. This method returns a MongoCommandCursor object. This cursor object	implements
       the Iterator interface just like the MongoCursor objects that are returned by the MongoCollection::find method.

       Note

	       The resulting MongoCommandCursor will inherit this collection's read preference.  MongoCommandCursor::setReadPreference may be used
	      to change the read preference before iterating on the cursor.

PARAMETERS

	      o $pipeline
		- The Aggregation Framework pipeline to execute.

	      o $options
		-Options for the aggregation command. Valid options include:

		     o "allowDiskUse"Allow aggregation stages to write to temporary files

		     o "cursor" It is possible to configure how many initial documents the server should return with the  first  result  set.  The
		       default initial batch size is 101. You can change it by adding the batchSize option:

		     <?php
		     $collection->aggregateCursor(
			 $pipeline,
			 [ "cursor" => [ "batchSize" => 4 ] ]
		     );
		     MongoCommandCursor::batchSize method on the returned MongoCommandCursor object.

		     o "explain"  Return information on the processing of the pipeline. This option may cause the command to return a result docu-
		       ment that is unsuitable for constructing a MongoCommandCursor. If you need to use this option, you  should  consider  using
		       MongoCollection::aggregate.

		     o "maxTimeMS"Specifies  a cumulative time limit in milliseconds for processing the operation (does not include idle time). If
		       the operation is not completed within the timeout period, a MongoExecutionTimeoutException will be thrown.

RETURN VALUES

	Returns a MongoCommandCursor object. Because this implements the Iterator interface you can iterate over each of the results  as  returned
       by  the	command query. The MongoCommandCursor also implements the MongoCursorInterface interface which adds the MongoCommandCursor::batch-
       Size, MongoCommandCursor::dead, MongoCommandCursor::info methods.

EXAMPLES

       Example #1

	      MongoCollection.aggregateCursor(3) example

	       Finding all of the distinct values for a key.

	      <?php
	      $m = new MongoClient;
	      $db = $m->test;
	      $people = $db->people;
	      $people->drop();

	      $people->insert(array("name" => "Joe", "points" => 4));
	      $people->insert(array("name" => "Molly", "points" => 43));
	      $people->insert(array("name" => "Sally", "points" => 22));
	      $people->insert(array("name" => "Joe", "points" => 22));
	      $people->insert(array("name" => "Molly", "points" => 87));

	      $ages = $people->aggregateCursor( [
		      [ '$group' => [ '_id' => '$name', 'points' => [ '$sum' => '$points' ] ] ],
		      [ '$sort' => [ 'points' => -1 ] ],
	      ] );

	      foreach ($ages as $person) {
		  echo "{$person['_id']}: {$person['points']}
";
	      }

	      ?>

	      The above example will output something similar to:

	      Joe: 26 Sally: 22

       Example #2

	      MongoCollection.aggregateCursor(3) example with different initial batch size

	       Finding all of the distinct values for a key.

	      <?php
	      $m = new MongoClient;
	      $db = $m->test;
	      $people = $db->people;
	      $people->drop();

	      /* Insert some sample data */
	      $people->insert(array("name" => "Joe", "points" => 4));
	      $people->insert(array("name" => "Molly", "points" => 43));
	      $people->insert(array("name" => "Sally", "points" => 22));
	      $people->insert(array("name" => "Joe", "points" => 22));
	      $people->insert(array("name" => "Molly", "points" => 87));

	      /* Run the command cursor */
	      $ages = $people->aggregateCursor(
		  [
		      [ '$group' => [ '_id' => '$name', 'points' => [ '$sum' => '$points' ] ] ],
		      [ '$sort' => [ 'points' => -1 ] ],
		  ],
		  [ "cursor" => [ "batchSize" => 4 ] ]
	      );

	      foreach ($ages as $person) {
		  echo "{$person['_id']}: {$person['points']}
";
	      }

	      ?>

	      The above example will output something similar to:

	      Joe: 26 Sally: 22

SEE ALSO

       MongoDB::command, MongoCommandCursor, MongoCommandCursor::batchSize, MongoCollection::aggregate, The MongoDB aggregation framework.

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