Mysql UPDATE function is editing right, but creates a new empty row at the end of the table

Question

I’m racking my brain here, because function UPDATE works well when used neatly by the terminal or Workbench, but when I do the PHP code via HTML form parameters, it edits neatly too, but creates a new empty line, and creates more and more empty lines each time you edit something. And this does not happen via terminal and workbench. (I thought it had something to do with the date in TIMESTAMP, so I deleted the date field from BD and PHP but the problem continued).

<h1> Editar </h1>
<form method="post" action="<?php require('editar.php'); echo htmlspecialchars($_SERVER["PHP_SELF"]) ?>" >

id: <br><input type="number" name="id_upd">
<br><br>

Nome: <br><input type="text" name="nome_upd">
<br><br>

Localização: <br><input type="text" name="localizacao_upd">

<br><br>

E-mail: <br><input type="text" name="email_upd">
<br><br>

Website: <br><input type="text" name="website_upd">
<br><br>

Gênero:
<input type="radio" name="genero_upd" value="Feminino">Feminino
<input type="radio" name="genero_upd" value="Masculino">Masculino

<br><br>

Mensagem:<br> 
<textarea name="mensagem_upd" rows="10" cols="50"></textarea>
<br>

<input type="submit" name="submit" value="Submit"> 

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

try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    $edit = $id_upd = $nome_upd = $localizacao_upd = $email_upd = $website_upd = $genero_upd = $mensagem_upd = "";

//Inserindo os dados de entrada do usuário recebidos do formulário HTML nas váriaveis
if ($_SERVER["REQUEST_METHOD"] == "POST") {

    $id_upd = $_POST["id_upd"];
    $nome_upd = $_POST["nome_upd"];
    $localizacao_upd = $_POST["localizacao_upd"];
    $email_upd = $_POST["email_upd"];
    $website_upd = $_POST["website_upd"];
    $genero_upd = $_POST["genero_upd"];
    $mensagem_upd = $_POST["mensagem_upd"];

}

//Se a entrada do usuário for diferente de "" (vazio) edite o nome para nova entrada.
if($nome_upd != "") {
        //Variável $sql recebe a notação de UPDATE MySQL com parâmetros (os valores serão a entrada do usuário)
        $sql = "UPDATE guestbook SET nome='".$nome_upd."' WHERE id='".$id_upd."'";

        //Preparação de confirmação individual
        $stmt = $conn->prepare($sql);

        //Execução da preparação individual
        $stmt->execute();
}

if($localizacao_upd != "") {
        $sql = "UPDATE guestbook SET localizacao='".$localizacao_upd."' WHERE id='".$id_upd."'";
        $stmt = $conn->prepare($sql);
        $stmt->execute();
}

if($email_upd != "") {
        $sql = "UPDATE guestbook SET email='".$email_upd."' WHERE id='".$id_upd."'";
        $stmt = $conn->prepare($sql);
        $stmt->execute();
}

if($website_upd != "") {
        $sql = "UPDATE guestbook SET website='".$website_upd."' WHERE id='".$id_upd."'";
        $stmt = $conn->prepare($sql);
        $stmt->execute();
}

if($genero_upd != "") {
        $sql = "UPDATE guestbook SET genero='".$genero_upd."' WHERE id='".$id_upd."'";
        $stmt = $conn->prepare($sql);
        $stmt->execute();
}

 if($mensagem_upd != "") {
        $sql = "UPDATE guestbook SET mensagem='".$mensagem_upd."' WHERE id='".$id_upd."'";
        $stmt = $conn->prepare($sql);
        $stmt->execute();
 }
}
catch(PDOException $e) {
    echo $sql . "<br>" . $e->getMessage();
}

$conn = null;
?>

Answer 1

Editing usually works this way, by clicking on the link of the listing page the user is redirected to the editar.php, in it is done database search by id, which was passed by $_GET.

Listing.php

$row is listing of all records, has a while/foreach before this link.

<a href="cadastros/editar.php?id=<?php echo $row['id']>EDITAR</a>"

Edit.php

Do the search by id, with the value received in $_GET['id'], then close the php tag, create the html of the form, in each field add the attribute value and open the php tag and write the value of the respective field with $registro['nome_do_campo'].

I recommend creating a new file(gravar.php) to update and update.

How do you know when to include or update the record? If there is a value in the field id_udp it is an update of the opposite is an Insert.

<?php
    include 'conexao.php';

    $id = !empty($_GET['id']) ? $_GET['id'] : 0;

    $sql = "SELECT * FROM guestbook WHERE id = :id"
    $stmt = $db->prepare($sql);
    $stmt->bindValue(':id', $id);
    $stmt->execute();

    $registro = $stmt->fetch(PDO::FETCH_ASSOC);

?>

<form method="post" action="gravar.php">

id: <br><input type="hidden" name="id_upd" value="<?php echo $registro['id'];" />
<br><br>

Nome: <br>
      <input type="text" name="nome_upd" value="<?php echo $registro['nome_upd'];" />
<br><br>

Localização: <br><input type="text" name="localizacao_upd" value="<?php echo $registro['localizacao_upd'];" />  

demais campos ...

</form>