CODEWITHSUNDEEP
phpsql
Jeff
Jeff

Reputation: 23

HTML button to run SQL command

I'm a bit of a noob at php/sql (well all languages in general), I am trying to get an sql command to run on the click of a html button.

The sql command that I am trying to run is UPDATE supplies SET quantity = quantity + 1 WHERE Id=1

This is what I have at the moment:

dp.php

<?php
$servername = "localhost";
$dbname = "tonor";
$username = "root";
$password = "password";

    try {
        $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
        $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    } catch(PDOException $e) {
        echo "Connection failed: " . $e->getMessage();
    }
?>

index.php

<!DOCTYPE html>
<html>
    <head>
    <?php 
        require_once 'db.php';

        if(isset($_POST['data'])){
            $sth = $conn->prepare("UPDATE supplies SET quantity = quantity + 1 WHERE Id=1");
            $sth->execute();
        }
    ?>
    <title>Homepage</title>
    <link rel="stylesheet" type="text/css" href="style/main.css">
</head>
<body>
    <h1>testpage</h1>
    <form method="POST" action="index.php">
        <input type="submit" name="data" value="1"/>
    </form>

Upvotes: 0

Views: 9814

Answers (2)

Eddie Kaka Svensson
Eddie Kaka Svensson

Reputation: 29

I am answering on john's post.

The reason it executes every time you reload the page is because the browser resends the post data to the server. You need to use header() to redirect on post. Your code is not perfect but it works. You should organize it. Maybe place all database logic in a class. An example of redirection that works for this example.

<?php 
    if(isset($_POST['data']))
    {
        require 'db.php';
        $sth = $conn->prepare("UPDATE supplies SET quantity = quantity + 1 WHERE Id=1");
        $sth->execute();
        header("Location: {$_SERVER['SERVER_NAME'].$_SERVER['REQUEST_URI']}");
        die("Posted, now redirecting");
    }
?>

Upvotes: 1

Stark
Stark

Reputation: 593

You should try this out, but you need to read, and practice further.

PDO manual: http://php.net/manual/en/book.pdo.php

It's a lot to look at, but just take a look at their examples to get an idea of how it works.

Read this as well to make it easier: https://code.tutsplus.com/tutorials/why-you-should-be-using-phps-pdo-for-database-access--net-12059

PHP is a server side language.

I any case, the following should be enough to get you started.

 <?php
    $servername = "localhost";
    $dbname = "databasename";
    $username = "username";
    $password = "password";

    try {
        $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
        $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    } catch(PDOException $e) {
        echo "Connection failed: " . $e->getMessage();
    }

    return $conn;
?>


<!DOCTYPE html>
<html>
    <head>
    <?php 
        require 'db.php';

        if(isset($_POST['data'])){
            $sth = $conn->prepare("UPDATE supplies SET quantity = quantity + 1 WHERE Id=1");
            $sth->execute();
        }
    ?>
    <title>Homepage</title>
    <link rel="stylesheet" type="text/css" href="style/main.css">
</head>
<body>
    <h1>testpage</h1>
    <form method="POST" action="">
        <input type="submit" name="data" value="1"/>
    </form>

</body>
</html>

Upvotes: 2

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