sql database query issues - php

Question

For the last week a have been stuck on one part of my website, the register script. I have got it to create new users in the database which is fine however it when someone enters a duplicate user name that I have issues with.
The database is set up to not allow duplicated so if you try you get a lovely error printed on the web page and although functional doesn't look great.,
what I have been trying to do and have looked at many many examples of how to do it but it never works for me. I Would love some help and please don't be a jerk and say there are answers/ it's a duplicate because I have tried. If you don't want to help then move on :).
here is the code:
<?php
include 'pdo_connect.php';
if(!empty($_POST)) {
$uname = $_POST['uname'];
$upassword = password_hash($_POST['upassword'], PASSWORD_DEFAULT);
//here i want to search for the duplicate username and if none then carry on ar if match echo "alredy taken"
$query = 'INSERT INTO `users` ( `uname`, `password`) VALUES (?,?)'; //if duplicate exists returns a duplicate error.
$params = array($uname, $upassword);
$results = dataQuery($query, $params);
}
?>
UPDATE 1
<?php
include 'pdo_connect.php';
if(!empty($_POST)) {
$uname = $_POST['uname'];
$upassword = password_hash($_POST['upassword'], PASSWORD_DEFAULT);
//here i want to search for the duplicate username and if none then carry on ar if match echo "alredy taken"
try
{
$query = 'INSERT INTO `users` ( `uname`, `password`) VALUES (?,?)'; //if duplicate exists returns a duplicate error.
}
catch (Exception $e)
{
echo "username taken";
}
$params = array($uname, $upassword);
$results = dataQuery($query, $params);
}
?>
tried the try catch as suggested but same issue the server error is displayed on screen i think its because it still executes and it doesnt "crash".
here is the error i get: (when i try to register as admin which already exists)
error
UPDATE 2
same result :(
<?php
include 'pdo_connect.php';
if(!empty($_POST)) {
$uname = $_POST['uname'];
$upassword = password_hash($_POST['upassword'], PASSWORD_DEFAULT);
//here i want to search for the duplicate username and if none then carry on ar if match echo "alredy taken"
try
{
$query = 'INSERT INTO `users` ( `uname`, `password`) VALUES (?,?)'; //if duplicate exists returns a duplicate error.
$params = array($uname, $upassword);
$results = dataQuery($query, $params);
}
catch (Exception $e)
{
echo "username taken";
}
}
?>
UPDATE 2
<?php
include 'pdo_connect.php';
if(!empty($_POST)) {
$uname = $_POST['uname'];
$upassword = password_hash($_POST['upassword'], PASSWORD_DEFAULT);
//here i want to search for the duplicate username and if none then carry on ar if match echo "alredy taken"
try
{
$query = 'INSERT INTO `users` ( `uname`, `password`) VALUES (?,?)'; //if duplicate exists returns a duplicate error.
$params = array($uname, $upassword);
$results = dataQuery($query, $params);
}
catch (PDOException $e)
{
echo "username taken";
}
}
?>
still does the same :(
UPDATE 3
<?php
include 'pdo_connect.php';
if (!empty($_POST)) {
$uname = $_POST['uname'];
$upassword = password_hash($_POST['upassword'], PASSWORD_DEFAULT);
//here i want to search for the duplicate username and if none then carry on ar if match echo "alredy taken"
try {
$query = $ConString->prepare("SELECT * from users where uname = $uname ");
$query->execute([$uname]);
$results = $query->fetchall();
if (count($results) > 0) {
echo "username taken";
} else {
$query = 'INSERT INTO `users` ( `uname`, `password`) VALUES (?,?)';
$params = array($uname,$upassword);
$results = dataQuery($query, $params);
}
}
catch (Exception $e) {
echo "username taken";
}
}
?>
these 2 errors:
enter image description here
pdo_connect code:
<?php
error_reporting(E_ALL);
ini_set('display_errors', 1);
define('USER', 'root');
define('PASS', 'pass');
function dataQuery($query, $params) {
$queryType = explode(' ', $query);
// establish database connection
try {
$dbh = new PDO('mysql:host=localhost;dbname=test', USER, PASS);
$dbh->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}
catch(PDOException $e) {
echo $e->getMessage();
$errorCode = $e->getCode();
}
// run query
try {
$queryResults = $dbh->prepare($query);
$queryResults->execute($params);
if($queryResults != null && 'SELECT' == $queryType[0]) {
$results = $queryResults->fetchAll(PDO::FETCH_ASSOC);
return $results;
} else {
return $queryResults->rowCount();
}
$queryResults = null; // first of the two steps to properly close
$dbh = null; // second step tp close the connection
}
catch(PDOException $e) {
$errorMsg = $e->getMessage();
echo $errorMsg;
}
}
?>

Answer 1

Before insert you will need to run a select statement, select id or what ever from you users table that matches the username supplied on register, if the select statement return results then the username is taken otherwise run the insert.
<?php
include 'pdo_connect.php';
if (!empty($_POST)) {
$uname = $_POST['uname'];
$upassword = password_hash($_POST['upassword'], PASSWORD_DEFAULT);
//here i want to search for the duplicate username and if none then carry on ar if match echo "alredy taken"
try {
$query = $ConString->prepare("SELECT * from users where uname = ? ");
$query->execute([$uname]);
$results = $query->fetchall();
if (count($results) > 0) {
echo "username taken";
} else {
$query = 'INSERT INTO `users` ( `uname`, `password`) VALUES (?,?)';
$params = array($uname,$upassword);
$results = dataQuery($query, $params);
}
}
catch (Exception $e) {
echo "username taken";
}
}
?>
You will need to modify my code to match with your methods, because as it stand you have done your own sql functions.

Answer 2

found it!
error_reporting(E_ALL);
ini_set('display_errors', 1);
define('USER', 'root');
define('PASS', 'Unhackable');
function dataQuery($query, $params) {
// what kind of query is this?
$queryType = explode(' ', $query);
// establish database connection
try {
$dbh = new PDO('mysql:host=localhost;dbname=test', USER, PASS);
$dbh->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}
catch(PDOException $e) {
echo $e->getMessage();
$errorCode = $e->getCode();
}
// run query
try {
$queryResults = $dbh->prepare($query);
$queryResults->execute($params);
if($queryResults != null && 'SELECT' == $queryType[0]) {
$results = $queryResults->fetchAll(PDO::FETCH_ASSOC);
return $results;
} else {
return $queryResults->rowCount();
}
$queryResults = null; // first of the two steps to properly close
$dbh = null; // second step tp close the connection
}
catch(PDOException $e) {
$errorMsg = $e->getMessage();
echo "too slow, username already taken";
//echo $errorMsg;
}
}
?>
commented out echoing the error message and echoing a customised message, i know its not great but it does the job.