PHP unlink() not working to delete files - php

Question

I am have been trying to setup this code to delete a row on the mysql database as well as the photo that was uploaded with it. It is working GREAT to remove the row data, but it will not get rid of the photo, and I cannot figure out what I am doing wrong. To simplify things, im using the variable $id which is the number of the row entered in the form which triggers this php file:
<?php
$host="localhost"; // Host name
$username="blahblah_plans"; // Mysql username
$password="password"; // Mysql password
$db_name="blahtbl_name"; // Database name
$tbl_name="plans"; // Table name
// Connect to server and select databse.
$conn = mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot select DB");
// get value of id that sent from address bar
$id=$_GET['idnum'];
$compositesql="SELECT composite FROM plans WHERE ID ='$id'";
$compositeresult = mysql_query($compositesql) or die(mysql_error());
$compositefilename = "/composite/" + $compositeresult;
$unlink = unlink($compositefilename);
if($unlink) {
echo 'Successfully deleted file: ';
echo $compositefilename;
} else {
echo 'Error deleting file: ';
echo $compositefilename;
}
// Delete data in mysql from row that has this id
$sql="DELETE FROM $tbl_name WHERE ID ='$id'";
$result = mysql_query($sql);
if($result){
header("location:planentry.php");
}
else {
echo "ERROR";
}
?>
<?php
// close connection
mysql_close();
?>

Answer 1

Make sure the path is right, $compositefilename = "/composite/" + $compositeresult; should be the path in the server, it most likely to be
$compositefilename = PATH_TO_YOUR_WEB_ROOT . "/composite/" . $compositeresult;
And php does not use + to concat strings.

Answer 2

The problem is that $compositeresult contains a resource rather than a result set. This line is what's causing it:
$compositeresult = mysql_query($compositesql) or die(mysql_error());
To fix that, store the resource on a variable, then store the result set on another variable, like this:
$compositequery = mysql_query($compositesql) or die(mysql_error());
$compositeresult = mysql_fetch_array($compositequery) or die(mysql_error());
Also, I highly recommend that you start using mysqli or PDO instead of mysql, since it's safer. Also, as xdazz said, PHP's concatenation operator is the dot, not the plus sign. So your $compositefilename should be declared as (note that $compositeresult is an array of data and therefore should have its correct key explicitly written):
$compositefilename = "/composite/" . $compositeresult['composite'];