如何实现记账系统的数据同步和备份功能 - 使用PHP开发数据同步和备份的方法

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";

$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
?>

<?php
// 源数据库连接
$source_conn = new mysqli("source_server", "source_username", "source_password", "source_database");

// 目标数据库连接
$target_conn = new mysqli("target_server", "target_username", "target_password", "target_database");

// 查询源数据库中的数据
$source_data = $source_conn->query("SELECT * FROM source_table");

// 将数据插入或更新到目标数据库
while ($row = $source_data->fetch_assoc()) {
    $target_conn->query("INSERT INTO target_table (column1, column2) VALUES ('" . $row['column1'] . "', '" . $row['column2'] . "') ON DUPLICATE KEY UPDATE column1 = '" . $row['column1'] . "', column2 = '" . $row['column2'] . "'");
}

//关闭数据库连接
$source_conn->close();
$target_conn->close();
?>

<?php
// 数据库连接
$conn = new mysqli("server", "username", "password", "database");

// 导出数据库中的数据
$result = $conn->query("SELECT * INTO OUTFILE '/path/to/backup.sql' FROM table");

if ($result) {
    echo "Backup successful!";
} else {
    echo "Backup failed!";
}

//关闭数据库连接
$conn->close();
?>