如何使用PHP数据库连接实现数据的同步和复制

<?php
// 数据库连接信息
$servername = "localhost";
$username = "db_username";
$password = "db_password";
$dbname = "db_name";

try {
    // 建立数据库连接
    $pdo = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    // 设置错误模式为异常
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    echo "数据库连接成功";
} catch(PDOException $e) {
    echo "数据库连接失败: " . $e->getMessage();
}
?>

<?php
// 源数据库连接信息
$source_servername = "source_db_server";
$source_username = "source_db_username";
$source_password = "source_db_password";
$source_dbname = "source_db_name";

// 目标数据库连接信息
$target_servername = "target_db_server";
$target_username = "target_db_username";
$target_password = "target_db_password";
$target_dbname = "target_db_name";

try {
    // 建立源数据库连接
    $source_pdo = new PDO("mysql:host=$source_servername;dbname=$source_dbname", $source_username, $source_password);
    $source_pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    // 建立目标数据库连接
    $target_pdo = new PDO("mysql:host=$target_servername;dbname=$target_dbname", $target_username, $target_password);
    $target_pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    // 获取源数据
    $stmt = $source_pdo->query("SELECT * FROM source_table");
    $results = $stmt->fetchAll(PDO::FETCH_ASSOC);

    // 将源数据插入目标数据库
    foreach ($results as $row) {
        // 构建插入语句
        $values = implode(",", array_map(function ($value) use ($target_pdo) {
            return $target_pdo->quote($value);
        }, $row));

        // 执行插入语句
        $target_pdo->query("INSERT INTO target_table VALUES ($values)");
    }

    echo "数据复制成功";
} catch(PDOException $e) {
    echo "数据复制失败: " . $e->getMessage();
}
?>

0 * * * * /usr/bin/php /path/to/your/script.php >/dev/null 2>&1