Automatically writes to database

[saunders1989]

i am trying to create a very simple comment form underneath images. i have the form set up, and i have some code. but when i go on to the image i get an unsigned variable and it will automatically write to the database and the comments box will be blank. when i type in the comments box and click submit the text does actually get written to the db but i need it to stop automatically writing that first time when you arrive on the page. could someone please help.

here is my code i have:

<?php
$dbLink = new mysqli('localhost', 'root', '', 'gallery');
if(mysqli_connect_errno()) {
die("MySQL connection failed: ". mysqli_connect_error());
}

if(isset($_GET['id']) && is_numeric($_GET['id'])) {
/* $_GET['id'] passes our test, so perform security functions on it & assign it to the $id variable */
$id= $dbLink->real_escape_string($_GET['id']);
} else {
/* it doesn't exist or it isn't numeric so assign a default value so our query below always gets constructed properly & safely */
$id = 1;
}

/* construct the query */
$query = "SELECT name, size, viewed_path, description FROM images WHERE id = $id";

/* run the query */
$result = $dbLink->query($query, MYSQLI_STORE_RESULT); 

while($row = $result->fetch_array()) { 

echo "<div id=\"image\">\n";
echo "<img src=\"" . $row['viewed_path'] . "\" alt=\"" . $row['name'] . "\" />\n";  
echo "</div>\n";

echo '<p>' . $row['description'] . '</p>';

} 
?>


<FORM METHOD="POST" action="">
<INPUT TYPE="text" NAME="name" SIZE="30">
<INPUT TYPE="text" NAME="surname" SIZE="30">
<textarea NAME="comment" ROWS=6 COLS=40></textarea>
<input type="submit" name="Comment" value="Comment">  

</FORM>

<?php

$comments = $dbLink->real_escape_string($_POST['comment']);

$query = "INSERT INTO `image_comments`(`image_id`, `comments`) VALUES ('{$id}', '{$comments}')";

$results = $dbLink->query($query, MYSQLI_STORE_RESULT);

$query1 = "SELECT comments FROM image_comments WHERE id = $id";

$result = $dbLink->query($query1, MYSQLI_STORE_RESULT);
?>

this is the error i get:

Notice: Undefined index: comment in C:\wamp\www\Blean_Photos\image.php on line 77

but if i click submit i dont get that error after.

[Bjom]

$comments = $dbLink->real_escape_string($_POST['comment']);

You are referencing the $_POST array here. Since that array only gets 'built' after the submit, it won't have any indices the first time the script runs - that's what causes the error.

Since I don't believe you want to write unless there has been a submit in advance I suggest you surround the last 5 lines with something along

if (isset($POST['comment'])) {

// your code

}

[saunders1989]

the error has dissappeared 🙂 but when i go onto that page it automatically writes to the database a blank comment in essence. does that make sense. if so any ideas how to fix it?

thanks for the if statement i didnt think of that

[Bjom]

same as above

[saunders1989]

it seems to have fixed itself somehow. it was writing automatically earlier.

thanks

[Bjom]

nothing ever fixes itself. It's pretty important that you understand your own code...

[saunders1989]

oh i fully undestanding it is checking to see if it has been 'posted' and if it has it does that bit of code. could you help me with this issue of when my comments are being displayed?

<?php
if (isset($_POST['comment'])){

$comments = $dbLink->real_escape_string($_POST['comment']); 

$query = "INSERT INTO `image_comments`(`image_id`, `comments`) VALUES ('{$id}', '{$comments}')";

$results = $dbLink->query($query, MYSQLI_STORE_RESULT);

}

$query1 = "SELECT comments FROM image_comments WHERE id = $id";

$results = $dbLink->query($query1, MYSQLI_STORE_RESULT);

while($row = $results->fetch_array()) {

echo '<table>';
echo '<tr>';
	echo '<td>' . $row['comments'] . '</td>';
echo '</tr>';
echo '</table>';
}

?>

i thought that would display the comments but im not getting them to display.

[Bjom]

$query1 = "SELECT comments FROM image_comments WHERE id = $id";

should be

$query1 = "SELECT comments FROM image_comments WHERE image_id = $id";

maybe that's it?

[saunders1989]

yep that was it 🙂. thank you soo much. it goes to show you cant code stuff in the early morning without making a silly mistake like that.

thankyou for pointing that out!