Display Hierarchical Data MySQL Error

[reisve]

Hi

I'm trying to adapt a function to Display Hierarchical Data I found on sitepoint
The code I got so far is:
 

<?php
// $parent is the parent of the children we want to see 
// $level is increased when we go deeper into the tree, 
//        used to display a nice indented tree 
$link = mysql_connect("localhost", "root", "palhaco");
if (!$link) {
    die('Could not connect: ' . mysql_error());
}

$db_selected = mysql_select_db('testecat', $link);
if (!$db_selected) {
    die ('Can\'t use foo : ' . mysql_error());
}

function display_children($parent, $level) { 
    // retrieve all children of $parent 
    $result = mysql_query('SELECT title FROM testcat '. 
                           'WHERE parent="'.$parent.'";'); 
    // display each child 
    while ($row = mysql_fetch_array($result, MYSQL_ASSOC)) { 
        // indent and display the title of this child 
        echo str_repeat('  ',$level).$row['title']."\n"; 
        // call this function again to display this 
        // child's children 
        display_children($row['title'], $level+1); 
    } 
} 
display_children('',0); 
?>

But the only thing I got is an error message:

"Warning: mysql_fetch_array() expects parameter 1 to be resource, boolean given in D:\Web Data\testcat.php on line 20 "

Can some one help me please?

 

[Barand]

I use this version which doesn't continually query the database

<?php
include("testDBconnect.php");

$sql = "SELECT category_id, name, parent
        FROM category";
$res = mysql_query($sql);
while (list($id, $name, $parent) = mysql_fetch_row($res)) {
    $data[$parent][] = array('id'=>$id, 'name'=>$name);
}
    

// call the recursive function
displayHierarchy($data, 0);

// function to print a category then its child categories 
function displayHierarchy(&$arr, $parent, $indent=0)
{
    $ind = $indent * 50;
    if (isset($arr[$parent]))
    foreach($arr[$parent] as $rec)
    {
        echo "<div style='width:300px; margin-top:5px; margin-left: {$ind}px; padding:5px; border:1px solid gray;'>
        {$rec['name']}
        </div>" ;
        displayHierarchy($arr, $rec['id'], $indent+1);
    }
    
}
?>

[reisve]

It worked. Now I need to output the categories to a combobox

that should be easy

 

ThankYou