Undefined Index - Even with Isset If statement - php

Question

Can anyone tell me why I am getting an Undefined Index error on my code here.
I have used this setup using the if(isset) condition in other parts of my project after
researching my original Undefined Index errors and ISSET fixed my problems. But it is not working here for some reason and I cannot see why.
This form is POSTING the input:
<form action="addAlbum_Processed.php" method="POST">
<p>Enter artistID of Artist<input type="number" name="artist_id" maxlength="2" size="2"></p>
<p>Enter name of Album to be created<input type="text" name="album_name" size="20"></p>
<input type="submit" name="submit" value="submit"></form>
and this page is processing the form input and updating the albums table in my database:
<?php
$connection = mysql_connect('localhost','root','')
or die(mysql_error());
echo "Connected to php Server <br>";
or die("Could not select assi2 database");
echo "Connected to assi2 database <br>";
if(isset($_POST['submit']))
{
$album_name = $_POST['album_name'];
$artist_id = $_POST['artist_id'];
}
$album_name = $_POST['album_name'];
$artist_id = $_POST['artist_id'];
$sqlQuery = "SELECT * FROM albums WHERE album = '{$album_name}'";
$result = mysql_query($sqlQuery, $connection) or die("Selection Query Failed !!!");
if (mysql_num_rows($result) != 0)
{
header ("Location: Album_Exists.html");
}
else
{
$sqlInsert = "INSERT INTO albums (ArtistID, Album, delete_marker)
VALUES ('{$artist_id}','{$album_name}','delete_marker = 0')";
$result = mysql_query($sqlInsert, $connection) or die("Selection Query Failed !!!");
header ("Location: addAlbum_Processed.php");
}
mysql_close($connection);
?>
I cannot see where I am going wrong. Regards, TW

Answer 1

This is a tiny example of your problem:
if(isset($_POST['submit']))
{
$album_name = $_POST['album_name'];
$artist_id = $_POST['artist_id'];
}
You check whether a submit form field was posted before using the other fields. So far, so good. (I would check for the fields that were going to be used, but at least you're checking something.)
But then:
$album_name = $_POST['album_name'];
$artist_id = $_POST['artist_id'];
You use the fields anyway.
What's more...you don't keep from trying to insert stuff if a form isn't being posted. So any time some rogue spider visits your page, you end up with a blank album in your database.
And that's not even mentioning the fact that you're still using mysql_query.

Answer 2

if(isset($_POST['submit']))
{
$album_name = $_POST['album_name'];
$artist_id = $_POST['artist_id'];
}
|__________________________| first
$album_name = $_POST['album_name'];
$artist_id = $_POST['artist_id'];
|_________________________| Repeated
you are fetching variables twice.only one that is if condition is enough.Also use isset for both the variables.
if(isset($_POST['submit']))
{
if isset($_POST['album_name'])
$album_name = $_POST['album_name'];
if isset($_POST['artist_id'])
$artist_id = $_POST['artist_id'];
}

Answer 3

Try something like in addalbam_process.php
<?php
$connection = mysql_connect('localhost','root','')
or die(mysql_error());
echo "Connected to php Server <br>";
or die("Could not select assi2 database");
echo "Connected to assi2 database <br>";
if(isset($_POST['submit']))
{
if(isset($_POST['albam_name']){$album_name = $_POST['album_name']};
if(isset($_POST['artist_id']){$artist_id = $_POST['artist_id']};
}
$sqlQuery = "SELECT * FROM albums WHERE album = '{$album_name}'";
$result = mysql_query($sqlQuery, $connection) or die("Selection Query Failed !!!");
if (mysql_num_rows($result) != 0)
{
header ("Location: Album_Exists.html");
}
else
{
$sqlInsert = "INSERT INTO albums (ArtistID, Album, delete_marker)
VALUES ('{$artist_id}','{$album_name}','delete_marker = 0')";
$result = mysql_query($sqlInsert, $connection) or die("Selection Query Failed !!!");
header ("Location: addAlbum_Processed.php");
}
mysql_close($connection);
Please, use MYSQLI or PDO to Prevent SQL INJECTION

Answer 4

here </form> is missing
and try something like this
if(isset($_POST['submit']))
{
$album_name = $_POST['album_name'];
$artist_id = $_POST['artist_id'];
}

Answer 5

A few things.
This line 'delete_marker = 0' should most probably read as
VALUES ('{$artist_id}','{$album_name}','0')
or VALUES ('{$artist_id}','{$album_name}',0)
As I read it 'delete_marker = 0' you are attempting to actually write this value inside the delete_marker column (ArtistID, Album, delete_marker)
Or, you're attempting to use a WHERE delete_marker = 0 clause, which can't be used in an INSERT INTO, but an UPDATE or SELECT rather.
And your if(isset($_POST['submit'])) conditional statement should be wrapping your entire code, instead of just your 2 form variables, because it's basically saying "Ok, assign these 2 variables, then ignore the rest if it's NOT set."
Plus, you're repeating those 2 input variables.
$album_name = $_POST['album_name'];
$artist_id = $_POST['artist_id'];
(I wrapped your entire code inside the if(isset($_POST['submit'])) conditional statement, btw.
Side note: If you're having a DB connection issue, use this instead:
$connection = mysql_connect('localhost', 'root', '');
if (!$connection) {
die('Could not connect: ' . mysql_error());
}
echo 'Connected successfully';
PHP Give this a try:
Sidenote: If this line fails VALUES ('{$artist_id}','{$album_name}', 0) put quotes around the 0 as in '0'
<?php
$connection = mysql_connect('localhost','root','')
or die(mysql_error());
echo "Connected to php Server <br>";
or die("Could not select assi2 database");
echo "Connected to assi2 database <br>";
if(isset($_POST['submit']))
{
$album_name = $_POST['album_name'];
$artist_id = $_POST['artist_id'];
$sqlQuery = "SELECT * FROM albums WHERE album = '{$album_name}'";
$result = mysql_query($sqlQuery, $connection) or die("Selection Query Failed !!!");
if (mysql_num_rows($result) != 0)
{
header ("Location: Album_Exists.html");
}
else
{
$sqlInsert = "INSERT INTO albums (ArtistID, Album, delete_marker)
VALUES ('{$artist_id}','{$album_name}', 0)"; // or add quotes around the zero
$result = mysql_query($sqlInsert, $connection) or die("Selection Query Failed !!!");
header ("Location: addAlbum_Processed.php");
}
} // closing brace for if(isset($_POST['submit']))
mysql_close($connection);
?>