Its nothing to do with databases and its really pretty simple, its called a 'dynamic include', what it does is use a variable in an include to change the content of your page when a link is clicked, to put it simply if the following link were to be pressed it would declare the variable 'content' on the page 'index.php as 'pic_menu:
<b>http://www.danhall.co.uk/index.php?content=pic_menu</b>
the code on index.php looks as follows:
<b>
<?
if ($content==NULL) {
$content = 'news'; }
include($content . '.php');
?>
</b>
this is placed in the position where you want the content to load, as you can see, this is where the variable 'content' is used.
<u><b>Disection of the code:</b></u>
<b><?</b>
This is the opening wrapper which defines a peice of php code.
<b>if ($content==NULL)
{</b>
This statement means 'if the variable 'content' has nothing in it then..
<b>$content = 'news';
}</b>
considering that the last statement is true then the variable content will contain the value 'news'. (this 'if' statement makes sure that if no value has been passed onto the variable 'content' then it will equal 'news' by default.
<b>include($content . '.php');</b>
This is the actuall include that utilizes the variable 'content'. this is regular php include but it uses a variable ('content') to declare the name of the file to be included, as you can see it adds '.php' to the variable input, and so making a file name
<b>?></b>
The closing wrapper for a peice of php code
<u><b>Recap:</b></u>
To set the variable 'content' with a link:
<b>http://www.danhall.co.uk/index.php?content=forum<b/>
this will open forum.php on index.php
<b>http://www.danhall.co.uk/index.php<b/>
this will open news.php on index.php because it is the default
Hope this helps ypu make yaself a funky site peeps