Request_Sample.php

<?php

session_start();
$requested_sample_id = htmlspecialchars($_GET['Blood_Sample_Id']);
$useremail = $_SESSION['useremail'];

include 'Connect_to_Database.php';

$query = " ";
$query1 = " ";
$query = "SELECT * FROM view_requests WHERE (request_id=$requested_sample_id and user_email='$useremail')";

if ($result = mysqli_query($link, $query)) {

	if (mysqli_fetch_row($result) == 0) {
		$query1 = "INSERT into view_requests(request_id,user_email) values ($requested_sample_id,'$useremail')";
		if (mysqli_query($link, $query1)) {
			echo "<script type='text/javascript'>alert('Request Placed')</script>";
			header("refresh:0,url=Available_Sample.php");
		}
	} else {
		echo "<script type='text/javascript'>alert('Error!! Duplicate Request')</script>";
		header("refresh:0,url=Available_Sample.php");
	}
}