Bread Crumbs Nav Links, Recursive Array, PDO - php

Question

I have a database table with two columns for page URL's and URL parents, like this:
URL | Parent
Animal | (null)
Mammal | Animal
Tiger | Mammal
I'm trying to convert it to PDO. This is the original script:
$TopnavTable = 'gz_life';
$TopnavName = 'Taxon';
function get_path($node, $TopnavTable, $TopnavName) {
$result = mysql_query('SELECT Parent FROM ' . $TopnavTable . ' WHERE ' . $TopnavName . '="'.$node.'";');
$row = mysql_fetch_array($result);
$path = array();
if ($row['Parent']!='') {
$path[] = $row['Parent'];
$path = array_merge(get_path($row['Parent'], $TopnavTable, $TopnavName), $path);
}
return $path;
}
switch ($MyPage)
{
case 'ChildPage':
$TopNav = str_replace('Carnivora', '', $TopNav);
break;
default:
break;
}
$mypath = get_path($MyURL, $TopnavTable, $TopnavName);
$MyLink = $mypath;
$MyLink = str_replace('Life', '', $MyLink);
$MyDisplay = $mypath;
for($i=0;$i<count($mypath);$i++){
$TopNav = " ".$MyDisplay[$i]." >";
$That = array('<a href="Life">', '"> ', '>', '<a href="');
$This = array('<a href="/Life/">', '">', '> ', '<a href="/Life/');
$TopNav = str_replace($That, $This, $TopNav);
Someone just helped me upgrade a similar query, where the parent-child relationship is based on URL's. For example, the URL MySite/Topics/Washington/Governor should yield bread crumbs navigation links that look like this:
Topics > Washington > Governor
This is the code:
$TopnavTable = 'pox_topics';
$TopnavName = 'URL';
function get_path($dbh,$node,$TopnavTable, $TopnavName) {
$stmt = $dbh->prepare("SELECT name FROM $TopnavTable WHERE $TopnavName = ?");
$stmt->bindValue(1,$node);
$stmt->execute();
$stmt->setFetchMode(PDO::FETCH_ASSOC);
$row = $stmt->fetch();
$path = array_merge(get_path($pdo,$row['Parent'], $TopnavTable, $TopnavName), $path);
return $path ;
}
$Path2 = explode("/", $path);
$arrlength=count($Path2);
$html =''.$Path2[0].' > ';//First Member
for($x=1;$x<$arrlength-1;$x++) {//Between first & last
$html .= ''.$Path2[$x].' > ' ;
}
$html .= '<span class="navHere"><b>'.$Path2[$x].'</b></span>'; //Last member
$html = str_replace('/'.$MySection.'/'.$MySection.'', '/'.$MySection.'', $html);
echo $html ;
I was advised to read up on hierarchical data # http://mikehillyer.com/articles/managing-hierarchical-data-in-mysql/ In fact, I think that's what my original script posted at the top is based on.
Anyway, I thought I could modify the PDO script above to make it work with my hierarchical DB table, but I've been striking out, as usual.
Can anyone tell me what I need to change? (I deleted $Path2 = explode("/", $path); of course, but I never made any progress beyond that.)