MongoDB\Driver\Cursor::isDead

(mongodb >=1.0.0)

MongoDB\Driver\Cursor::isDeadChecks if the cursor is exhausted or may have additional results

Beschreibung

final public MongoDB\Driver\Cursor::isDead ( void ) : bool

Checks whether there are definitely no additional results available on the cursor. This method is similar to the » cursor.isExhausted() method in the MongoDB shell and is primarily useful when iterating » tailable cursors.

A cursor has no additional results and is considered "dead" when one of the following is true:

  • The current batch has been fully iterated and the cursor ID is zero (i.e. a » getMore cannot be issued).
  • An error was encountered while iterating the cursor.
  • The cursor reached its configured limit.

By design, it is not possible to always determine whether a cursor has additional results. The cases where a cursor may have more data available is as follows:

  • There are additional documents in the current batch, which are buffered on the client side. Iterating will fetch a document from the local buffer.
  • There are no additional documents in the current batch (i.e. local buffer), but the cursor ID is non-zero. Iterating will request more documents from the server via a » getMore operation, which may or may not return additional results and/or indicate that the cursor has been closed on the server by returning zero for its ID.

Parameter-Liste

Diese Funktion besitzt keine Parameter.

R├╝ckgabewerte

Returns TRUE if there are definitely no additional results available on the cursor, and FALSE otherwise.

Fehler/Exceptions

  • Throws MongoDB\Driver\InvalidArgumentException on argument parsing errors.

Beispiele

Beispiel #1 MongoDB\Driver\Cursor::isDead() example

<?php

$manager 
= new MongoDB\Driver\Manager("mongodb://localhost:27017");
$query = new MongoDB\Driver\Query([]);

$bulk = new MongoDB\Driver\BulkWrite;
$bulk->insert(['x' => 1]);
$bulk->insert(['x' => 2]);
$bulk->insert(['x' => 3]);
$manager->executeBulkWrite('db.collection'$bulk);

$cursor $manager->executeQuery('db.collection'$query);

$iterator = new IteratorIterator($cursor);

$iterator->rewind();
var_dump($cursor->isDead());

$iterator->next();
var_dump($cursor->isDead());

$iterator->next();
var_dump($cursor->isDead());

$iterator->next();
var_dump($cursor->isDead());

?>

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

bool(false)
bool(false)
bool(false)
bool(true)

Siehe auch

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