Value not saving after form is submitted - php

Question

I've created a mysql table with two columns. One is ID and other is Heading. I have a textarea on which I run UPDATE code and whenever someone submits a form its being updated in the datebase column under heading. And that works fine but I want to show the last inputted submit inside my textarea.
My code is showing the last inputted value but when I reset the page it all turns out blank and its not showing anymore. I looked out in datebase and the heading is still there so I don't know why its dissapearing from the front end.
My page:
<?php
$title = 'Admin Panel - Edit';
include '../config.php';
$heading = mysqli_real_escape_string($link, $_REQUEST['heading']);
$sql = "UPDATE content SET heading='$heading' WHERE id = 1 ";
if(mysqli_query($link, $sql) == false){
echo "ERROR: Could not able to execute $sql. " . mysqli_error($link);
}
$value=mysqli_query($link, "SELECT heading FROM content WHERE id = 1");
$currentText = mysqli_fetch_row($value);
?>
<form action="edit.php">
<?php echo $currentText[0]; ?>
<input type="text" name="heading" id="heading" value='<?php echo $currentText[0]; ?>' />
<input type="submit" value="Submit" name="submit" />
</form>
So for example if I type Aleksa, after submit it will get url like edit.php?heading=Aleksa&submit=Submit. And then when I delete url just to edit.php, the value is missing.
You can test the page here: https://www.easybewussterschaffen.com/admin/edit.php

Answer 1

This is happening, because it's always trying to insert the heading when you refresh the page. You should check to see if the request is GET or the request is POST, and only insert it if they're submitting the form.
Update your form method, specify it to POST, and specifically check the method or check for the existance of $_POST['submit'] as shown below:
<?php
$title = 'Admin Panel - Edit';
include '../config.php';
// Use one of the 2 if statements:
if ($_SERVER['REQUEST_METHOD'] === 'POST') { // Trying to insert a new heading
if (isset($_POST['submit'])) { // Alternative
$heading = mysqli_real_escape_string($link, $_REQUEST['heading']);
$sql = "UPDATE content SET heading='$heading' WHERE id = 1 ";
if(mysqli_query($link, $sql) == false){
echo "ERROR: Could not able to execute $sql. " . mysqli_error($link);
}
}
$value=mysqli_query($link, "SELECT heading FROM content WHERE id = 1");
$currentText = mysqli_fetch_row($value);
?>
<form action="edit.php" method="POST">
<?php echo $currentText[0]; ?>
<input type="text" name="heading" id="heading" value='<?php echo $currentText[0]; ?>' />
<input type="submit" value="Submit" name="submit" />
</form>
Alternatively, if you still wish to make a GET request, you should check to make sure that the heading is set:
<?php
$title = 'Admin Panel - Edit';
include '../config.php';
if (isset($_GET['submit'])) {
$heading = mysqli_real_escape_string($link, $_GET['heading']);
$sql = "UPDATE content SET heading='$heading' WHERE id = 1 ";
if(mysqli_query($link, $sql) == false){
echo "ERROR: Could not able to execute $sql. " . mysqli_error($link);
}
}
$value=mysqli_query($link, "SELECT heading FROM content WHERE id = 1");
$currentText = mysqli_fetch_row($value);
?>
<form action="edit.php" method="GET">
<?php echo $currentText[0]; ?>
<input type="text" name="heading" id="heading" value='<?php echo $currentText[0]; ?>' />
<input type="submit" value="Submit" name="submit" />
</form>

Answer 2

I did it like this, is this good tho? Its working
<?php
$sql = "SELECT * FROM content";
if($result = mysqli_query($link, $sql)){
if(mysqli_num_rows($result) > 0){
echo '';
while($row = mysqli_fetch_array($result)){
echo $row['heading'];
}
// Free result set
mysqli_free_result($result);
} else{
echo "No records matching your query were found.";
}
} else{
echo "ERROR: Could not able to execute $sql. " . mysqli_error($link);
}
?>