The MongoCursor class

Introduction

Result object for database query.

A MongoCursor has two "life stages": pre- and post- query. A cursor can be created manually by calling the constructor, but it is most often created by calling MongoCollection::find(). When a cursor is created, it has not yet contacted the database, so it is in its pre-query state. In this state, the client can further specify what they want the query to do, including adding limits, skips, sorts, and more advanced options.

When the client attempts to get a result (by calling MongoCursor::next(), directly or indirectly), the cursor moves into the post-query stage. At this point, the query has been executed by the database and cannot be modified anymore. At this point, the only functions available are the Iterator functions, MongoCursor::hasNext(), and MongoCursor::getNext().

<?php

$cursor = $collection->find()->limit(10);

// database has not yet been queried, so more search options can be added
$cursor = $cursor->sort(array("a" => 1));

var_dump($cursor->getNext());
// now database has been queried and more options cannot be added

// so this will throw an exception:
$cursor->skip(4);
?>

Class synopsis

implements Iterator {

/* Static Fields */

static boolean $slaveOkay = FALSE ;

static integer $timeout = 20000 ;

/* Methods */

public MongoCursor addOption ( string $key , mixed $value )

__construct ( resource $connection , string $ns [, array $query = array() [, array $fields = array() ]] )

public int count ([ boolean $foundOnly = FALSE ] )

public array current ( void )

public boolean dead ( void )

protected void doQuery ( void )

public array explain ( void )

public MongoCursor fields ( array $f )

public array getNext ( void )

public boolean hasNext ( void )

public MongoCursor hint ( array $key_pattern )

public MongoCursor immortal ([ boolean $liveForever = true ] )

public array info ( void )

public string key ( void )

public MongoCursor limit ( int $num )

public void next ( void )

public void reset ( void )

public void rewind ( void )

public MongoCursor skip ( int $num )

public MongoCursor slaveOkay ([ boolean $okay = true ] )

public MongoCursor snapshot ( void )

public MongoCursor sort ( array $fields )

public MongoCursor tailable ([ boolean $tail = true ] )

public MongoCursor timeout ( int $ms )

public boolean valid ( void )

}

Static Variables

MongoCursor::slaveOkay

If the query should have the "slaveOkay" flag set, which allows reads on the slave (slaves are, by default, just for backup and unreadable). Can be overridden with MongoCursor::slaveOkay().

MongoCursor::timeout

Set timeout in milliseconds for all database responses. To wait forever, use -1. Can be overridden with MongoCursor::timeout(). This does not cause the MongoDB server to cancel the operation, it just causes the driver to stop waiting for a response and throw a MongoCursorTimeoutException.

See Also

MongoDB core docs on » cursors.