I did something similar to that very thing today...
I'm using DataAssist to Update the record...
$WA_connection = $dbconnect;
$WA_table = "consultants";
$WA_redirectURL = "";
$WA_keepQueryString = false;
$WA_indexField = "consultant_rec_id";
$WA_fieldNamesStr = "fname|lname|title|emailaddress|password|status|group|phone_number";
$WA_fieldValuesStr = "".((isset($_POST["fname"]))?$_POST["fname"]:"") ."" . "|" . "".((isset($_POST["lname"]))?$_POST["lname"]:"") ."" . "|" . "".((isset($_POST["title"]))?$_POST["title"]:"") ."" . "|" . "".((isset($_POST["email_address"]))?$_POST["email_address"]:"") ."" . "|" . "".((isset($_POST["password"]))?$_POST["password"]:"") ."" . "|" . "".((isset($_POST["status"]))?$_POST["status"]:"") ."" . "|" . "".((isset($_POST["group"]))?$_POST["group"]:"") ."" . "|" . "".((isset($_POST["phone"]))?$_POST["phone"]:"") ."";