php操作主从mysql

<?php
// 连接主数据库
$master_host = 'master_host';
$master_user = 'master_user';
$master_pass = 'master_pass';
$master_db = 'master_db';

$master_conn = mysqli_connect($master_host, $master_user, $master_pass, $master_db);

if (!$master_conn) {
    die('连接主数据库失败: ' . mysqli_connect_error());
}

// 连接从数据库
$slave_host = 'slave_host';
$slave_user = 'slave_user';
$slave_pass = 'slave_pass';
$slave_db = 'slave_db';

$slave_conn = mysqli_connect($slave_host, $slave_user, $slave_pass, $slave_db);

if (!$slave_conn) {
    die('连接从数据库失败: ' . mysqli_connect_error());
}

// 写操作（主数据库）
$sql = "INSERT INTO table_name (column1, column2) VALUES ('value1', 'value2')";
if (mysqli_query($master_conn, $sql)) {
    echo "数据写入成功";
} else {
    echo "数据写入失败: " . mysqli_error($master_conn);
}

// 读操作（从数据库）
$sql = "SELECT * FROM table_name";
$result = mysqli_query($slave_conn, $sql);

if ($result) {
    while ($row = mysqli_fetch_assoc($result)) {
        echo "ID: " . $row['id'] . " - Name: " . $row['name'] . "<br>";
    }
} else {
    echo "读取数据失败: " . mysqli_error($slave_conn);
}

mysqli_close($master_conn);
mysqli_close($slave_conn);
?>