MongoDB\Driver\Cursor::isDead

    (mongodb >=1.0.0)

    MongoDB\Driver\Cursor::isDead — Checks if the cursor is exhausted or may have additional results

    Опис

    final public MongoDB\Driver\Cursor::isDead(): 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.

    Параметри

    У цієї функції немає параметрів.

    Значення, що повертаються

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

    Помилки/виключення

    Приклади

    Приклад #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());

    ?>

    Поданий вище приклад виведе:

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

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