.htaccess 301动态重定向匹配数据库

I have incoming url http://www.example.com/index.html?id=1234

I have database WORDS with 2 columns: 'id' and 'url'

I need to 301 redirect matching the id parameter in url (1234) to corresponding URL, such as:

http:// www.example.com/index.html?id=1234 becomes http:// www.redirectedurl.com

I tried something similar as what is explained here I think the correct way is having a simple .htaccess code that uses a php file to match ids with urls in database but i don't know where to start.

Thanks for your help!

<?php

    //Check if GET value is set
    if(isset($_GET["id"]){

        //Retrieve values from database
        $db = new PDO(/* connect to your database here */);
        $stmt = $db->prepare("SELECT `url` FROM `table` WHERE `id`=? LIMIT 1");

        //If the statement doesn't execute
        if(!$stmt->execute(array(trim($_GET["id"])))) exit("Could not connect to database!");

        //If there are no rows returned
        if($stmt->rowCount()<1) exit("Could not find ID!");

        //Data is correct - redirect the user!
        $row = $stmt->fetch(PDO::FETCH_ASSOC);
        $url = $row["url"];
        header("Location: ".$url);
        exit;            
    } else {
        echo "No ID set!";
    }