如何使用PostgreSql的CURRVAL /从另一个php文件返回？

<?php
$host = "your_host";
$port = "your_port";
$dbname = "your_dbname";
$user = "your_username";
$password = "your_password";

$db = pg_connect("host=$host port=$port dbname=$dbname user=$user password=$password");
if (!$db) {
    echo "Error: Unable to connect to PostgreSQL database.";
    exit;
}
?>

<?php
// 引入包含数据库连接的文件
require_once 'your_database_connection_file.php';

// 执行查询获取CURRVAL值
$query = "SELECT CURRVAL('your_sequence_name')";
$result = pg_query($db, $query);
if (!$result) {
    echo "Error: Unable to execute query.";
    exit;
}

// 获取查询结果
$row = pg_fetch_row($result);
$currval = $row[0];

// 输出CURRVAL值
echo "CURRVAL: " . $currval;
?>