Delete statement using PDO, PHP and MYSQL using primaryKey & checkBox - php

Question

I'm trying to delete multiple entry in database. I'm using a checkbox to determine what data I need to delete. Once I tick the checkbox, its sending me the value of my primary key which I use to delete it. So far I have come up with this
when I try to delete single or multiple data, it goes straight to success page which successfully count the number of intended amount of deleted player. But nothing happens when I show all tables.
HTML/PHP code
<?php
$self = htmlentities($_SERVER['PHP_SELF']);
echo "<form id='delete' method='POST' action='$self'>";
?>
<div class="content">
<h3>Delete Athlete</h3>
<hr>
<table>
<tr>
<th>Select Player</th><th>Photo</th><th>First Name</th><th>Last Name</th><th>Gender</th><th>Sport</th><th>Country</th><th>Population</th><th>Flag</th>
</tr>
<?php
foreach($showResult as $row)
{
echo("<tr><td><input type='checkbox' name='checkdelete[]' value='$row[athleteID]'>$row[athleteID]</td>
<td><img class='photo' src='files/$row[image]' alt='$row[lastName].jpg'/></td>
<td>$row[firstName]</td><td>$row[lastName]</td>
<td><img class='genderImg' src='files/$row[gender].png' alt='$row[gender].jpg'/></td>
<td>$row[sport]</td><td>$row[countryName]</td><td>$row[population]</td>
<td><img class = 'flag' src='files/flags/$row[flag]' alt='$row[flag].jpg'/></tr>");
}
?>
</table>
<br><input type="submit" name="deleteAth" value="Delete">
</div>
</body>
and I have this code for PHP
<?php
include 'connect.inc.php';
try // select statement for the output page/delete page
{
$showJoinedTbl = "SELECT athleteID,image, firstName, lastName, gender, sport,
countryName, population, flag from athTbl join
counTbl on athTbl.countryID = counTbl.countryID ORDER by firstName";
$showResult = $pdo->query($showJoinedTbl);
}
catch (PDOException $e)
{
$error = 'Select statement error';
include 'error.html.php';
exit();
}
$dataCorrect = true;
if (isset($_POST['deleteAth']))
{
try
{
$valueID = $_POST['checkdelete'];
$N = count ($valueID);
for ($i=0; $i; $i++)
{
$deleteQry = $db->prepare("DELETE from athTbl WHERE athleteID= ?");
echo ("$valueID[$i]");
//$stmt = $pdo->prepare($deleteQry);
$stmt->bindValue(1,$valueID[$i]);
$stmt->execute();
} //when I try to delete single or multiple data, it goes straight to success page which successfully count the number of intended amount of deleted player. But nothing happens when I show all tables.
}
catch (PDOException $e)
{
$error = 'Error deleting data from athleteTbl';
include 'error.html.php';
exit();
}
include 'DeleteSuccess.html.php'; // output screen if I deleted it successfully.
}
else
{
include 'Delete.html.php';
}
?>

Answer 1

You have an error in your loop:
...
$N = count ($valueID);
for ($i=0; $i; $i++)
^^ 0 on the first iteration
{
...
Your loop will run while the condition (the middle value) is true. You set $i to 0 which evaluates to false so your loop never runs.
Or, from the manual:
In the beginning of each iteration, expr2 is evaluated. If it
evaluates to TRUE, the loop continues and the nested statement(s) are
executed. If it evaluates to FALSE, the execution of the loop ends.
You probably want:
...
$N = count ($valueID);
for ($i=0; $i < $N; $i++)
{
...