在PHP5面向对象中获取大量数据的正确方法

class DataGenerator {
    private $data = [];

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

    public function getData() {
        foreach ($this->data as $item) {
            yield $item;
        }
    }
}

$data = range(1, 100000);
$generator = new DataGenerator($data);

foreach ($generator->getData() as $item) {
    // 处理数据
}

// PDO 示例
$pdo = new PDO('mysql:host=localhost;dbname=test', 'username', 'password');
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

$stmt = $pdo->prepare('SELECT * FROM large_table');
$stmt->execute();

$stmt->setFetchMode(PDO::FETCH_ASSOC);
$iterator = new IteratorIterator($stmt);

foreach ($iterator as $row) {
    // 处理数据
}

$batchSize = 100;
$offset = 0;

while (true) {
    $data = getData($offset, $batchSize);

    if (empty($data)) {
        break;
    }

    foreach ($data as $item) {
        // 处理数据
    }

    $offset += $batchSize;
}

$file = new SplFileObject('large_data.txt', 'r');
$file->setFlags(SplFileObject::READ_CSV);

foreach ($file as $row) {
    // 处理数据
}