php - PDO 使用 PDO::FETCH_PROPS_LATE 和 __construct() 调用？

Question

我正在尝试创建一个新的 Setting 对象实例，调用 __construct() 方法，使用 PHP PDO 并约束 PDO::FETCH_PROPS_LATE。不幸的是，我收到此警告(并且绑定(bind)不起作用)。

如何将列值传递给构造方法？

Warning: Missing argument 1 for Setting::__construct() in pdo.php.

Notice: Undefined variable: key in pdo.php.

class Setting
{

    protected $key, $value, $displayable;

    public function __construct($key, $value = null, $displayable = 1)
    {
        $this->key         = $key;
        $this->value       = $value;
        $this->displayable = $displayable > 0;
    }

}

while($mashup = current($mashups))
{
    $stmt = $dbh->prepare('SELECT `key`, value, displayable
        FROM setting WHERE mashup_id = :id');

    $stmt->bindParam(':id', $mashup->id, PDO::PARAM_INT);
    $stmt->execute();

    $settings = $stmt->fetchAll(PDO::FETCH_CLASS|PDO::FETCH_PROPS_LATE,
       'Setting');
}

$stmt->closeCursor();

Answer 1

您的构造函数中有一个非默认参数 $key:

public function __construct($key, $value = null, $displayable = 1)

所以，当你这样做的时候:

$settings = $stmt->fetchAll(PDO::FETCH_CLASS|PDO::FETCH_PROPS_LATE,'Setting');

错误:警告:缺少参数 1 for Setting::__construct() in pdo.php 仅针对参数 $key 抛出，因为它不是默认值。

fetchAll(PDO::FETCH_CLASS|PDO::FETCH_PROPS_LATE,...的正确使用是这样的:

$variable = $stmt->fetchAll(PDO::FETCH_CLASS|PDO::FETCH_PROPS_LATE,
                           'classname', 
                            <array of parameter names(in order) used in constructor>);

因此，在您的情况下:

$variable = $stmt->fetchAll(PDO::FETCH_CLASS|PDO::FETCH_PROPS_LATE,
                            'Setting', 
                             array('key', 'value', 'displayable');