How can I trigger PHP if a MySQL gets a new highest ID?
Question
Im trying to make my Webpage do an action (in this case play a sound) on the event of the highest ID (auto_increment) in my SQL table increasing, which happens when a new user is registered. Eg : 3 users registered, highest ID = 3. When a new user registers, highest ID = 4. Webpage echos/plays sound if this happens. The Js and PHP, respectively:
<script type="text/javascript" src="jquery.js"></script> <script type="text/javascript"> $(document).ready(function() { setInterval(function () { $('#show').load('data.php') }, 3000); }); </script> <?php include ('../includes/dbh.inc.php'); if ($conn->connect_error) { die("Connection error: " . $conn->connect_error); } $result = $conn->query("SELECT * FROM signs WHERE id = (SELECT MAX(id) FROM signs)"); if ($result->num_rows > 0) { while ($row = $result->fetch_assoc()) { echo $row['firstName']; echo $row['lastName']; echo $row['inOrOut'] . '<br>'; $numId = $row['ID'] . '<br>'; echo $numId; } $value = 1; $value = $numId; if ($value < $numId) { //echo '<script type="text/javascript">play_sound();</script>'; echo "increased"; } else echo "nothing detected"; } } ?>
As you can tell, I tried doing something with comparing the last and the newest ID value but failed miserably.
My attempt would be to store an initial value for oldID and then comparing this to newID before replacing it.
2 answers
solution1
2 ACCPTED 2019-11-23 20:13:10
You can't do that only with PHP. But you could do it like this: If you have a website, you set the current highest ID in the output of php. You can use javascript to call another php script every 5 minutes (or any other time span you find meaningful) that gives you back the current highest number. If the number from the php script is higher, than the number you have in javascript, you can let javascript play a sound for you.
Assuming your php script returns an id like this:
{"id":4}
an example for the javascript call would be this:
<html>
<head></head>
<script>
let highestId = 2;
window.setInterval(async function(){
const response = await fetch('http://localhost/jstest/index.php');
const myJson = await response.json();
console.log(console.log(myJson.id));
if (highestId < myJson.id) {
highestId = myJson.id
// here you can play your sound
$s = document.getElementById('myId');
$s.innerHTML = highestId;
}
}, 5000);
</script>
<body>
<span id="myId">0</span>
</body>
</html>
solution2
1 2019-11-23 20:22:33
You can use a cookie variabale to do this. Set the cookie value using php and send the cookie value with php file call. This way you can identify a new highest id.
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript">
$(document).ready(function() {
setInterval(function () {
var id = getCookie("highest_id");
$('#show').load('data.php?id='+id)
}, 3000);
});
</script>
Add set cookie in the code if the value is changed.
<?php
include ('../includes/dbh.inc.php');
if ($conn->connect_error) {
die("Connection error: " . $conn->connect_error);
}
$result = $conn->query("SELECT * FROM signs WHERE id = (SELECT MAX(id) FROM signs)");
if ($result->num_rows > 0) {
$numId = 0;
if ($row = $result->fetch_assoc()) {
$numId = $row['id'];
}
$value = $_GET['id'] ?? 0;
if ($value < $numId) {
//echo '<script type="text/javascript">play_sound();</script>';
echo "increased";
setcookie("highest_id", $numId, time() - 3600);
} else {
echo "nothing detected";
}
}
?>
Note the points :
In PHP : setcookie("highest_id", $numId, time() - 3600);
In Script : getCookie("highest_id");
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.