Accessing from another function an extracted row from an sql table - php

Question

I have a php auxiliary function called extractFromID() in a file called auxiliary.php which queries a database for a specific line in a table which has a specific ID value and then extracts all the columns from that line.
function extractFromID() {
$connect = mysql_connect("localhost", "root","") or die ("erro a abrir a ligação.");
mysql_select_db ("hospitaldatabase");
$query = 'SELECT * FROM ' .$_SESSION['listtype']. ' WHERE (ID_' .$_SESSION['listtype']. '="'.$_SESSION['id'].'")';
$results = mysql_query($query) or die(mysql_error());
while($rows = mysql_fetch_array($results){
extract($rows);
}
}
From another file, I am trying to access the variables extracted by the function extractFromID() from $rows using
<?php
include('auxiliary.php');
extractFromID();
Although, I seem to be unable to access the extracted values, since I get undefined index errors. What am I doing wrong?

Answer 1

You need to understand variable scope. When you declare a variable inside a function, its scope is limited to that function. You can expand its scope by declaring it to be $GLOBAL but, in your case, the best solution is to return the values you want to use
function extractFromID() {
$connect = mysql_connect("localhost", "root","") or die ("erro a abrir a ligação.");
mysql_select_db ("hospitaldatabase");
$query = 'SELECT * FROM ' .$_SESSION['listtype']. ' WHERE (ID_' .$_SESSION['listtype']. '="'.$_SESSION['id'].'")';
$results = mysql_query($query) or die(mysql_error());
$data = array();
while($rows = mysql_fetch_assoc($results)){
$data[] = $rows;
}
return $data;
}
$myvars = extractFromId();
echo $myvars[0]['fieldname'];
As for undefined variables, it could be you've not called session_start() at the top of your pages before setting your $_SESSION variables. That would mean they are undefined.