通过魔术方法使用PDO :: FETCH_CLASS [英] Using PDO::FETCH_CLASS with Magic Methods

问题描述

我有一个使用魔术方法存储属性的类.这是一个简化的示例:

I have a class that uses magic methods to store properties. Here is a simplified example:

class Foo {
    protected $props;

    public function __construct(array $props = array()) {
        $this->props = $props;
    }

    public function __get($prop) {
        return $this->props[$prop];
    }

    public function __set($prop, $val) {
        $this->props[$prop] = $val;
    }
}

我正在尝试为PDOStatement的每个数据库行实例化此类的对象，如下所示(无效):

I'm trying to instantiate objects of this class for each database row of a PDOStatement after it's executed, like this (doesn't work):

$st->setFetchMode(PDO::FETCH_CLASS, 'Foo');

foreach ($st as $row) {
    var_dump($row);
}

问题在于，PDO::FETCH_CLASS似乎在设置属性值时不会触发类上的魔术__set()方法.

The problem is that PDO::FETCH_CLASS does not seem to trigger the magic __set() method on my class when it's setting property values.

如何使用PDO实现所需的效果?

推荐答案

PDO的默认行为是在调用构造函数之前先设置属性.设置构造函数后，设置获取方式来设置属性时，在位掩码中包含PDO::FETCH_PROPS_LATE，这将导致在未定义属性上调用__set魔术方法.

The default behavior of PDO is to set the properties before invoking the constructor. Include PDO::FETCH_PROPS_LATE in the bitmask when you set the fetch mode to set the properties after invoking the constructor, which will cause the __set magic method to be called on undefined properties.

$st->setFetchMode(PDO::FETCH_CLASS | PDO::FETCH_PROPS_LATE, 'Foo');

或者，创建一个实例并提取到其中(即，将提取模式设置为PDO::FETCH_INTO).

Alternatively, create an instance and fetch into it (i.e. set fetch mode to PDO::FETCH_INTO).

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