Setting active class and selecting specific row from DB

[eluser]Unknown[/eluser]
Hello,
I'm new to CodeIgniter and I'm currently trying to build the first website with it.

I'm pulling my navi and content from a DB.

First, the navi (model):

Code:

function getNavi()
    {
        $query = $this->db->get('content');
        
        if ($query->num_rows() == 0)
        {
            echo "Datenbank leer...";    
        } else {
            return $query->result();
        }
    }

And the view:

Code:

<?php foreach($navi as $kategorien): ?>
            <li>&lt;?php echo $kategorien->name; ?&gt;</li>
    &lt;?php endforeach; ?&gt;

This displays all the navi-buttons I have. What I'd like to do is to set a "class="active""for whatever site currently is active.

Also, I'm trying to select only the content-row of the currently active site. I tried with an ?id=1 URI-parameter and then setting $_GET['id'], but this won't work. Any other suggestions?

Also, I searched the forums and Google and didn't happen to find a solution to my 2 little problems.