How to prevent session variable get overwritten and display the result? - php

Question

*Below is my code
When I click search, it only display one result from my database.
Is there other method to solve this problem?
Or how to save multiple variables in the session and then display it?
<?php
session_start();
?>
<?php
include("htmltable.php");
?>
<table align="center">
<table class="data-table">
<caption class="title">Donor Lists</caption>
<thead>
<tr>
<th>DonorID</th>
<th>Donor</th>
<th>gender</th>
<th>bloodgroup</th>
<th>State</th>
</tr>
</thead>
<tbody>
<td><?php echo("{$_SESSION['DonorID']}"."<br />");?></td>
<td><?php echo("{$_SESSION['FullName']}"."<br />");?></td>
<td><?php echo("{$_SESSION['gender']}"."<br />");?></td>
<td><?php echo("{$_SESSION['bloodgroup']}"."<br />");?></td>
<td><?php echo("{$_SESSION['State']}"."<br />");?></td>
</tbody>
</table>
</table>
This is the process, when user search, it will select from the database and then display it at the search donor page.
<?php
session_start();
include "dbh.inc.php";
if (isset($_POST['submit']))
{
$sql="SELECT * FROM donorregistration WHERE (bloodgroup='{$_POST["bloodgroup"]}' AND State='{$_POST["State"]}')";
$result = mysqli_query($conn, $sql);
if (mysqli_num_rows($result) > 0)
{
while($row = mysqli_fetch_assoc($result))
{
$_SESSION['DonorID'] = $row['DonorID'];
$_SESSION['FullName'] = $row['FullName'];
$_SESSION['gender'] = $row['gender'];
$_SESSION['bloodgroup'] = $row['bloodgroup'];
$_SESSION['State'] = $row['State'];
header("Location: ../assignbloodbank/Searchdonor.php?search=success");
exit();
}
}
else
{
echo "<div class='alert alert-danger'><i class='fa fa-users'></i> No Donors Found</div>";
}
}
?>

Answer 1

When you use header("Location") inside of a while loop only the first redirect will work. And when you use exit() no further code will execute. Also, there's no need to set $_SESSION for every row (as that will overwrite the variable too, unless you use an array for each session value with $_SESSION['key'][]).
The easiest approach would be to simply craft your <table> inside of your if statement, and craft your table rows inside of your while loop:
<?php
if (mysqli_num_rows($result) > 0)
{
?>
<table>
<thead>
<tr>
<th>DonorID</th>
<th>Donor</th>
<th>gender</th>
<th>bloodgroup</th>
<th>State</th>
</tr>
</thead>
<tbody>
<?php
while($row = mysqli_fetch_assoc($result))
{
echo "<td>" . $row['DonorID'] . "</td>";
echo "<td>" . $row['FullName'] . "</td>";
echo "<td>" . $row['gender'] . "</td>";
echo "<td>" . $row['bloodgroup'] . "</td>";
echo "<td>" . $row['State'] . "</td>";
}
?>
</tbody>
</table>
<?php
}
?>
This way, the table itself only gets generated if there are rows returned from the database, meaning you'll never end up with a table with nothing in it.

Answer 2

You need to add new array in existing $_SESSION element rather than override the previous $_SESSION. Add this code in you while loop. if you want to print multiple records then you have to use foreach loop
$_SESSION['DonorID'][] = $row['DonorID'];
$_SESSION['FullName'][] = $row['FullName'];
$_SESSION['gender'][] = $row['gender'];
$_SESSION['bloodgroup'][] = $row['bloodgroup'];
$_SESSION['State'][] = $row['State'];
For printing multiple records use foreach loop
foreach ( $_SESSION as $row ) {
echo "<td>" . $row['DonorID'] . "</td>";
echo "<td>" . $row['FullName'] . "</td>";
echo "<td>" . $row['gender'] . "</td>";
echo "<td>" . $row['bloodgroup'] . "</td>";
echo "<td>" . $row['State'] . "</td>";
}

Answer 3

EDIT: The problem is due to you never place the session variable with array, hence your output from sql actually kept repeating overwrite inside the variable, that the reason why you able to acquire one result only.
What you can do is declare your session as array before store the data.
$_SESSION['DonorID'] = array();
$_SESSION['FullName'] = array();
$_SESSION['gender'] = array();
$_SESSION['bloodgroup'] = array();
$_SESSION['State'] = array();
Then retrieve your data using index. Make sure add your for new rows.
$counter=0;
$loopcounter=count($_SESSION['DonorID']);
while($counter < $loopcounter)
{
<tr><td><?php echo("{$_SESSION['DonorID'][$counter]}"."<br />");?></td>
.....</td></tr>
$counter++;
}
Reference: store mutiple values in php session