How to fetch and dispaly specific data with PDO - php

Question

I'm having issues making my project for lesson attendance and management work the way I'd like it to. Sorry if this has already been addressed here. After days of searching, I still cannot for the life of me find a way to display a limited result set from my DB query to my home page.
This part of the project gets all Towns listed on my homepage like so:
Verona
Mantova
Rovereto
Bardolino
...
What I'd rather want is to get control over whatever is displayed! Specifically, I'd like to have ONLY Rovereto and Bardolino returned (as example). I'm thinking of probably doing this with additional page e.g. index1.php so when this page is loaded it will show only desired values and not all fetched values!
The search function result is also case sensitive. If I type "Bardolino", I get result but with "bardolino", no joy at all. I'm new to this, please help me out. Thank you very much.
File index.php:
<table class="table">
<thead>
<tr>
<th>#</th>
<th>Lesson Number</th>
<th>Town</th>
</tr>
</thead>
<tbody>
<?php
for($i=0; $i < count(User::get_all_users()); $i++){
echo "<tr>";
echo "<td>".User::get_all_users()[$i]['id']."</td>";
echo "<td>".Lesson::get_lesson_by_id(User::get_all_users()[$i]['lesson_id'])['number']."</td>";
echo "<td>".show_town(Lesson::get_lesson_by_id(User::get_all_users()[$i]['lesson_id'])['town_id'])."</td>";
echo "</tr>";
}
?>
File user_controller.php:
if(isset($_GET['type']) && $_GET['type'] == 'search'){
global $user_search_list;
$user_search_list= array();
for($i=0; $i < count(User::get_all_users()); $i++){
$user = User::get_all_users()[$i];
$lesson_number = Lesson::get_lesson_by_id($user['lesson_id'])['number'];
$town_name = show_town(Lesson::get_lesson_by_id($user['lesson_id'])['town_id']);
if(strpos($lesson_number,$_GET['search_term']) !== False ||
strpos($town_name,$_GET['search_term']) !== False)
{
$user_search_list[] = $user;
}
}
$_SESSION['search_list'] = $user_search_list;
header("Location: search_user_list.php");
exit();
}
if(isset($_GET['type']) && $_GET['type'] == 'reserve'){
$user = User::get_user_by_id($_GET['user_id']);
if(!empty($_GET['seat_id'])) {
if(count($_GET['seat_id']) * $user['price'] > intval(Balance::get_user_balance($_SESSION['user_id'])['amount'])){
header("Location: reserve.php?user_id=".$user['id']."&balance_error=set");
exit();
}else{
foreach($_GET['seat_id'] as $seat_id){
echo $seat_id;
echo "<br>";
Reservation::create_reservation('', $_SESSION['user_id'], $_GET['user_id'], $seat_id, getdate()[0]);
Balance::update_balance($_SESSION['user_id'], intval(Balance::get_user_balance($_SESSION['user_id'])['amount']) - intval(User::get_user_by_id($_GET['user_id'])['price']));
Seat::reserve_seat($seat_id,$_SESSION['user_id']);
Action::create_action('', "User - ".$_SESSION['user_id'].'reserve Seat ID - '.$seat_id. " on User ID - ".$_GET['user_id'],"reserve" , getdate()[0]);
}
if(count(Reservation::get_all_reservations_by_user($_SESSION['user_id'])) == 5){
Balance::update_balance($_SESSION['user_id'] ,intval(Balance::get_user_balance($_SESSION['user_id'])['amount']) + 10);
header('Location: index.php?reserve_success=set&reward=set');
exit();
}
header('Location: index.php?reserve_success=set');
exit();
}
}
else{
header("Location: reserve.php?user_id=".$user['id']."&seat_error=set");
exit();
}
}
function show_town($id){
return Place::get_place_by_id(Town::get_town_by_id($id)['place_id'])['name'].
}
File User.php:
class User
{
static $id;
static $lesson_id;
static $starting_date;
static $starting_time;
static $arrival_time;
static $price;
static function create_user($id, $lesson_id, $starting_date, $starting_time, $arrival_time, $price){
global $db;
$sql = "INSERT INTO `lesson_database`.`users` (`id`, `lesson_id`, `starting_date`, `starting_time`, `arrival_time`, `price`) VALUES (NULL, '".$lesson_id."', '".$starting_date."', '".$starting_time."', '".$arrival_time."', '".$price."');";
$db_result = $db->query($sql);
if($db_result){
return True;
}
else{
return False;
}
}
static function get_all_users(){
global $db;
$sql = "SELECT * FROM `users`";
$db_result = $db->query($sql);
if($db_result){
return $db_result->fetchAll();
}
else {
return False;
}
}
static function get_user_by_id($id){
global $db;
$sql = "SELECT * FROM `users` WHERE `id` = '".$id."' LIMIT 1";
if(!isset($sql)){
echo "not set";
}
$db_result = $db->query($sql);
if($db_result){
$db_row = $db_result->fetch(PDO::FETCH_ASSOC);
if($db_row){
return $db_row;
}
else {
return False;
}
}
return False;
}
static function delete_user($id){
global $db;
$sql = "DELETE FROM `lesson_database`.`users` WHERE `users`.`id` = '".$id."'";
$db_result = $db->query($sql);
if($db_result){
return True;
}
else{
return False;
}
}
}

Answer 1

I feel a little bit like you've jumped ahead and skipped some basics as lots of this doesn't make sense.
Firstly, you've said about using PDO in the title but you're not using PDO in your queries, you really need to be using PDO so if you're not sure how then try and find a good tutorial about using prepared statements.
Secondly, you're doing loads of extra calls within loops and duplicating calls all over the place so I think you could do with looking for a tutorial on design patters and think about how you could streamline this code.
As a very basic you could get all your users once by using a fetchAll (or fetch_assoc i think in mysqli) and then just loop through that variable e.g.
<?php
$users = User::get_all_users;
foreach($users as $user){
$lesson = Lesson::get_lesson_by_id($user['lesson_id']);
echo "<tr>";
echo "<td>".$user['id']."</td>";
echo "<td>".$lesson['number']."</td>";
echo "<td>".show_town(lesson['lesson_id'])['town_id'])."</td>";
echo "</tr>";
}
as for your search the simplest way would be to pass a search string in the url and use global $_GET['searchString'] (obviously you will need to sanitize the string) and then search for results directly in sql such as
SELECT * FROM table WHERE town LIKE . $yourvariable .% (ideally in your newly learned PDO style)
then it will be both not case sensitive and will also mean you've got the data in the first place so you don't waste time looping through a bunch of extra rows.
If you need to make this case insensitive in the meantime then the simplest way is to convert the search and the comparison string to the same case (strtolower for example) and then they will match
It also strikes me that your database might not be in good shape as I would be surprised to find that a user table contains lesson ids, so you might want to look into the idea of database normalisation, this will then allow you to do some more creative queries and more easily gather together accurate information for whatever your task is (i.e. make it scalable and manageable).
I hope some of that is helpful, sorry it's not a quick answer but it's not a quick problem I think. Don't fear though, we all started somewhere!!