# phpman > perldoc > MongoDB::QueryResult

## NAME
    [MongoDB::QueryResult](https://www.chedong.com/phpMan.php/perldoc/MongoDB%3A%3AQueryResult/markdown) - An iterator for Mongo query results

## VERSION
    version v2.2.2

## SYNOPSIS
        $cursor = $coll->find( $filter );
        $result = $cursor->result;

        while ( $doc = $result->next ) {
            process_doc($doc)
        }

## DESCRIPTION
    This class defines an iterator against a query result. It automatically fetches additional
    results from the originating mongod/mongos server on demand.

    For backwards compatibility reasons, [MongoDB::Cursor](https://www.chedong.com/phpMan.php/perldoc/MongoDB%3A%3ACursor/markdown) encapsulates query parameters and generates
    a "[MongoDB::QueryResult](https://www.chedong.com/phpMan.php/perldoc/MongoDB%3A%3AQueryResult/markdown)" object on demand. All iterators on "[MongoDB::Cursor](https://www.chedong.com/phpMan.php/perldoc/MongoDB%3A%3ACursor/markdown)" delegate to
    "[MongoDB::QueryResult](https://www.chedong.com/phpMan.php/perldoc/MongoDB%3A%3AQueryResult/markdown)" object.

    Retrieving this object and iterating on it directly will be slightly more efficient.

## USAGE
### Error handling
    Unless otherwise explicitly documented, all methods throw exceptions if an error occurs. The
    error types are documented in [MongoDB::Error](https://www.chedong.com/phpMan.php/perldoc/MongoDB%3A%3AError/markdown).

    To catch and handle errors, the [Try::Tiny](https://www.chedong.com/phpMan.php/perldoc/Try%3A%3ATiny/markdown) and [Safe::Isa](https://www.chedong.com/phpMan.php/perldoc/Safe%3A%3AIsa/markdown) modules are recommended:

### Cursor destruction
    When a "[MongoDB::QueryResult](https://www.chedong.com/phpMan.php/perldoc/MongoDB%3A%3AQueryResult/markdown)" object is destroyed, a cursor termination request will be sent to
    the originating server to free server resources.

### Multithreading
    NOTE: Per threads documentation, use of Perl threads is discouraged by the maintainers of Perl
    and the MongoDB Perl driver does not test or provide support for use with threads.

    Iterators are cloned in threads, but not reset. Iterating from multiple threads will give
    unpredictable results. Only iterate from a single thread.

## METHODS
  has_next
        if ( $response->has_next ) {
            ...
        }

    Returns true if additional documents are available. This will attempt to get another batch of
    documents from the server if necessary.

  next
        while ( $doc = $result->next ) {
            process_doc($doc)
        }

    Returns the next document or "undef" if the server cursor is exhausted.

  batch
      while ( @batch = $result->batch ) {
        for $doc ( @batch ) {
          process_doc($doc);
        }
      }

    Returns the next batch of documents or an empty list if the server cursor is exhausted.

  all
        @docs = $result->all;

    Returns all documents as a list.

## AUTHORS
    *   David Golden <<david@mongodb.com>>

    *   Rassi <<rassi@mongodb.com>>

    *   Mike Friedman <<friedo@friedo.com>>

    *   Kristina Chodorow <<k.chodorow@gmail.com>>

    *   Florian Ragwitz <<rafl@debian.org>>

## COPYRIGHT AND LICENSE
    This software is Copyright (c) 2020 by MongoDB, Inc.

    This is free software, licensed under:

      The Apache License, Version 2.0, January 2004