Saving Google map Points to a database - php

Question

i have been playing with the Google maps trying to make a tour and save the start end and the way points in a database.
here is the java-script code that i use to pass the values
function saveRoute() {
var name = "<?php Print($log_username);?>";
var waypts = [];
var end = points.length-1;
var dest = points[end].LatLng;
if (document.getElementById("roundTrip").checked) {
end = points.length;
dest = points[0].LatLng;
}
data.start = {'lat': points[0].LatLng.lat(), 'lng': points[0].LatLng.lng()}
data.end = {'lat': dest.lat(), 'lng':dest.lng()}
for (var i=1; i<end; i++) {
waypts[i-1] = [points[i].LatLng.lat(),points[i].LatLng.lng()]
data.waypoints = waypts;
}
var str = JSON.stringify(data)
var jax = window.XMLHttpRequest ? new XMLHttpRequest() : new ActiveXObject('Microsoft.XMLHTTP');
jax.open('POST','process.php');
jax.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
jax.send('command=save&mapdata='+str)
jax.onreadystatechange = function(){ if(jax.readyState==4) {
if(jax.responseText.indexOf('bien')+1)alert('Updated');
else alert(jax.responseText)
}}
}
here is my php processing.php
<?
ob_start();
header('Cache-Control: no-store, no-cache, must-revalidate');
$data = $_REQUEST['mapdata'];
echo $data;
mysql_connect('localhost','root','');
mysql_select_db('mapdir');
if($_REQUEST['command']=='save')
{
$query = "update mapdir set value='$data'";
if(mysql_query($query))die('bien');
die(mysql_error());
}
if($_REQUEST['command']=='fetch')
{
$query = "select value from mapdir";
if(!($res = mysql_query($query)))die(mysql_error());
$rs = mysql_fetch_array($res,1);
die($rs['value']);
}
?>
i always get the ajax response as "updated" but nothing happens to the database
where i have gone wrong ?