PHP running script after reload with empty values

Question

I'm super new to PHP and I recently tried to create a "system" that adds customers to the SQLite database and displays them in a table. Well, every time I navigate to the HTML page in order to add a new customer, the script runs itself creating empty values within the database. When I click submit after filling the values it just works properly. Below I attach my code for this specific part of the "system".

    <!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>New Customer</title>
    <style>
        form {
            display:flex;
            flex-direction:column;
            width:65%;
            max-width:75%;
            margin:0 auto;
        }
    </style>
</head>
<body>
    <form action="" method="POST">
        <h1>Insert a new customer</h1>
        <label for="id">Customer Id</label>
        <input type="text" name="id" id="id">
        <label for="name">Customer Name</label>
        <input type="text" name="name" id="name">
        <label for="age">Customer Age</label>
        <input type="number" name="age" id="age">
        <label for="address">Customer Address</label>
        <input type="text" name="address" id="address">
        <button type="submit">Submit</button>
    </form>

    <?php 
    
    class COMPANY extends SQLite3 {
        function __construct() {
            $this->open('customers.db');
        }
    }
    
    $database = new COMPANY();

    if (!$database) {
        echo $database->lastErrorMsg();
    } else {
        echo "Database accessed!\n";
    }
   
    $insert ="INSERT INTO CUSTOMERS (ID, NAME, AGE, ADDRESS) VALUES ('".$_POST["id"]."', '".$_POST["name"]."', '".$_POST["age"]."','".$_POST["address"]."');";
    
    $result = $database->exec($insert);

    if(!$result) {
        echo $database->lastErrorMsg();
    } else {
        echo "Records added successfully!\n";
    }
    $database->close();
    ?>
   
</body>
</html>

As noted in the answer you don't ever check if form is actually submitted, you execute your database logic all the same. Your code will obviously grow, so can I suggest splitting your presentation and logic into separate files right now. It's easier than refactoring the thousand lines of spaghetti you end up with, if you don't split early. Other than that, see How can I prevent SQL injection in PHP? — Markus AO
– Markus AO, Commented Mar 12, 2022 at 15:13

Tushar Gupta · Accepted Answer · 2022-03-12 15:22:49Z

1

You need to use isset() and check if the form has actually posted the values. In your code, the page loads and PHP code executes without checking if the form has submitted and the blanks are inserted in the database

  if(isset($_POST['id'],isset($_POST['name'],isset($_POST['age'], isset($_POST['address']) {
 .. your code

  }

PS: this doesn't include sanitization and validation of fields, please add them as you wish

edited Mar 12, 2022 at 15:22

answered Mar 12, 2022 at 15:07

Tushar Gupta

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3 Comments

Coding_Harry Over a year ago

I'm entering this command on top of the code and it says that it expects a ")" instead of "}".

Tushar Gupta Over a year ago

oh thats because you have the class declaration at the start, please add it before $database = new COMPANY(); and close it after $database->close();

Coding_Harry Over a year ago

Done! Thanks so much for your precious help, wishing an amazing and productive weekend!

Sonali · Accepted Answer · 2022-03-12 16:18:28Z

0

There should be validation, values should not be empty.

edited Mar 12, 2022 at 16:18

answered Mar 12, 2022 at 15:26

Sonali

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1 Comment

Community Over a year ago

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