CODEWITHSUNDEEP
phpmysqlajax
zZShort_CircuitZz
zZShort_CircuitZz

Reputation: 185

Updating MySQL Table with AJAX

I am trying to send a value for an item in a MySQL table and increment its "availability" column by one.

A press of a button executes the following onclick function:

function updateStuff() {

// Data validation for string variable val 
// coordinating to one of the items in the SQL table

var xmlHttp = false;

if(window.ActiveXObject){  
    xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
else{
    xmlHttp = new XMLHttpRequest();
}

if(!xmlHttp)
    alert("Error : Cannot create xmlHttp object");
else{
    if(xmlHttp.readyState == 0 || xmlHttp.readyState == 4){
        xmlHttp.open("GET","update.php?val=" + val, true);
        xmlHttp.send(); 
    }
    else{
      setTimeout(updateStuff,1000);
      }
}

}

update.php looks like this:

<?php
header('Content-Type: text/xml');
echo '<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>';

echo '<response>';
$item = $_GET['val'];
echo 'You selected ' . $item;

$server = "localhost";
$user = "root";
$pass = "";
$datab = "checkout";

// Connect to database
$db = mysqli_connect($server, $user, $pass, $datab);

// Check connection
if (mysqli_connect_errno()){
echo "Could not connect to database: " . mysqli_connect_error();
}

$results = mysqli_query($db,"SELECT * FROM inventory WHERE item = " . $item);
$available = $results['available'] + 1;
$result = mysqli_query($db, "UPDATE inventory SET available = " . $available . " WHERE item = " + $item);

// Close connection 
mysqli_close($db);

echo '</response>';

?>

I think this is generally correct, unfortunately I'm not getting a table update when I execute the code. I am 100% confident in the validation for the variable val, and fairly confident with updateStuff(), but I'm less sure if I'm handling the server-side stuff corecctly with putting $_GET inside of response tags.

EDIT: I have made the syntax correction given by asparatu, but the problem persists.

Upvotes: 1

Views: 182

Answers (2)

Pathik Vejani
Pathik Vejani

Reputation: 4491

try this to update query:

$result = "UPDATE inventory SET available = "' .$available. '" WHERE item = "' .$item. '"";    
if (mysqli_query($db, $result)) {
    echo "Record updated successfully";
} else {
    echo "Error updating record: " . mysqli_error($db);
}

Upvotes: 0

asparatu
asparatu

Reputation: 128

The update query is wrong.

$result = mysqli_query($db, "UPDATE inventory SET available = available + 1 WHERE item = " + $item);

Where are you getting the current number for available?

you need a select statement that queries the current item and get current available amount then you can add one to it.

$results = mysqli_query($db,"SELECT * FROM inventory WHERE item = " . $item);
$available = $results['available'] + 1;

$result = mysqli_query($db, "UPDATE inventory SET available = " . $available . " WHERE item = " . $item);

That should work..

Upvotes: 1

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