隊列的資料結構與原理及其在PHP與MySQL中的應用

class Queue {
    private $queue;
  
    function __construct() {
        $this->queue = [];
    }
  
    function enqueue($item) {
        array_push($this->queue, $item);
    }
  
    function dequeue() {
        if ($this->isEmpty()) {
            return null;
        }
        return array_shift($this->queue);
    }
  
    function isEmpty() {
        return empty($this->queue);
    }
}

$taskQueue = new Queue();

$taskQueue->enqueue("Task 1");
$taskQueue->enqueue("Task 2");
$taskQueue->enqueue("Task 3");

while (!$taskQueue->isEmpty()) {
    $task = $taskQueue->dequeue();
    // 处理任务
    echo "Processing task: " . $task . "
";
    // 模拟任务执行时间
    usleep(rand(100000, 500000));
}

CREATE TABLE `message_queue` (
  `id` INT(11) NOT NULL AUTO_INCREMENT,
  `message` VARCHAR(255) NOT NULL,
  PRIMARY KEY (`id`),
  KEY `id_message_idx` (`id`, `message`)
) ENGINE=InnoDB;

-- 入队操作
INSERT INTO `message_queue` (`message`) VALUES ('Message 1');
INSERT INTO `message_queue` (`message`) VALUES ('Message 2');

-- 出队操作
SELECT `message` FROM `message_queue` ORDER BY `id` ASC LIMIT 1;
DELETE FROM `message_queue` ORDER BY `id` ASC LIMIT 1;