# MongoDB\Driver\WriteResult::getModifiedCount

(mongodb >=1.0.0)

MongoDB\Driver\WriteResult::getModifiedCount — Returns the number of existing documents updated

### 说明

final public MongoDB\Driver\WriteResult::getModifiedCount(): int

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

### 参数

此函数没有参数。

### 返回值

Returns the number of existing documents updated.

### 错误／异常

- Throws MongoDB\Driver\Exception\LogicException if the write was not acknowledged.
- Throws MongoDB\Driver\Exception\InvalidArgumentException on argument parsing errors.

### 更新日志

版本 | 说明
--- | ---
PECL mongodb 2.0.0 | 当针对未确认写入调用此方法时，现在会抛出异常，而不是返回 `null`。

### 示例

示例 #1 MongoDB\Driver\WriteResult::getModifiedCount() 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->getModifiedCount());
?>`

以上示例会输出：

    int(1)

### 参见

- MongoDB\Driver\WriteResult::getMatchedCount() - Returns the number of documents selected for update
- MongoDB\Driver\WriteResult::isAcknowledged() - Returns whether the write was acknowledged

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