Some very simple recursion to build a tree structure:
function buildTree(array $data, $parent = null) {
$branch = array();
foreach ($data as $row) {
if ($row['parent_id'] == $parent) {
$row['children'] = buildTree($data, $row['id']);
$branch[] = $row;
}
}
return $branch;
}
$tree = buildTree($rowsFromDatabase);
Having an explicit 'children'
key is usually preferable to the structure you’re proposing, but feel free to modify as needed.