Returns the number of documents selected for update

# MongoDB\Driver\WriteResult::getMatchedCount

(mongodb >=1.0.0)

MongoDB\Driver\WriteResult::getMatchedCount — Returns the number of documents selected for update

### 説明

final public MongoDB\Driver\WriteResult::getMatchedCount ( void ) : integer|null

If the update operation results in no change to the document (e.g. setting the value of a field to its current value), the matched count may be greater than the value returned by MongoDB\Driver\WriteResult::getModifiedCount().

### パラメータ

この関数にはパラメータはありません。

### 返り値

Returns the number of documents selected for update, or `NULL` if the write was not acknowledged.

### エラー / 例外

- 引数のパースに失敗した場合に MongoDB\Driver\Exception\InvalidArgumentException をスローします。

### 例

例1 MongoDB\Driver\WriteResult::getMatchedCount() example

`<?php
$manager = new MongoDB\Driver\Manager;
$bulk = new MongoDB\Driver\BulkWrite;
$bulk->insert(['x' => 1]);
$bulk->update(['x' => 1], ['$set' => ['y' => 3]]);
$bulk->update(['x' => 2], ['$set' => ['y' => 1]], ['upsert' => true]);
$bulk->update(['x' => 3], ['$set' => ['y' => 2]], ['upsert' => true]);
$bulk->delete(['x' => 1]);
$result = $manager->executeBulkWrite('db.collection', $bulk);
var_dump($result->getMatchedCount());
?>`

上の例の出力は以下となります。

    int(1)

### 参考

- MongoDB\Driver\WriteResult::getModifiedCount() - Returns the number of existing documents updated
- MongoDB\Driver\WriteResult::isAcknowledged() - Returns whether the write was acknowledged