Question

I’ve always found myself creating two separate php files/scripts for adding a certain data and editing this data. These files weren’t that much different, so I figured there should be a way how to make them into one file.

Here I’ll present a very simple example to illustrate my point:

add.php:

<?php

$title = $_POST['title']; // ignore the unescaped data, this is a simple example
$text = $_POST['text'];
mysqli_query($connection,
   "INSERT INTO `articles` (`title`, `text`) VALUES ('$title', '$text')");

echo'
<form>
   <input type="text" name="title" value="'.$_POST['title'].'" />
   <input type="text" name="text" value="'.$_POST['text'].'" />
   <input type="submit" value="Add" />
</form>
';

?>

edit.php:

<?php

$id = $_GET['id'];
$title = $_POST['title']; // ignore the unescaped data, this is a simple example
$text = $_POST['text'];
// save data
mysqli_query($connection,
   "UPDATE `articles` SET `title` = '$title', `text` = '$text'
    WHERE `id` = $id");

// get current data
$q = mysqli_query($connection,"SELECT * FROM `articles` WHERE `id` = $id");
$d = mysqli_fetch_array($q);
$title = $d['title'];
$text = $d['text'];

echo'
<form>
   <input type="text" name="title" value="'.$title.'" />
   <input type="text" name="text" value="'.$text.'" />
   <input type="submit" value="Add" />
</form>
';

?>

As you can see, the add and edit forms/codes are very similar, except that:

• add inserts the data, while edit updates it
• add inserts $_POST values into the form (if there’s an error, so that the submitted data remains in the form, while edit inserts the current database values into the form (after the save is complete and the page refreshes, so that the form has the current db values)

Can these two somehow be merged into one file/code, so that if I want to add/change the form values, I don’t need to edit two files separately, but will change the form only once?

Answer 1

You can use a INSERT ON DUPLICATE KEY UPDATE which roughly gave you :

<?php
$id = $_GET['id'];
$title = $text = '';

if ($_POST)
{
    $title = $_POST['title'];
    $text = $_POST['text'];
    // save data
    $query = "INSERT INTO `articles` (`id`, `title`, `text`)
              VALUES ('$id', '$title', '$text')
              ON DUPLICATE KEYS UPDATE title = title, text = text"
    mysqli_query($connection, $query);

}
else if ($id)
{
    // get current data
    $q = mysqli_query($connection, "SELECT * FROM `articles` WHERE `id` = $id");
    $d = mysqli_fetch_array($q);
    $title = $d['title'];
    $text = $d['text'];
}

echo '
<form>
   <input type="text" name="title" value="'.$title.'" />
   <input type="text" name="text" value="'.$text.'" />
   <input type="submit" value="Add" />
</form>';

• If it’s a POST and no $id present : a new row is inserted just like an INSERT.
• If it’s a POST and an $id is present : if $id already exist in the table than the row is updated otherwise it’s an INSERT.
• If you only have an $id : show the form with existing data in it.
• If it’s not a POST and $id isn’t populated : show an empty form.