How can I convert a hierarchical tree to parent-child relationships? - php

Question

At the moment, i'm creating a dynamic menu for my own CMS (practising) in PHP, but I don't know to save the data in my database.
Database structure:
menuitem_id
menu_id
menuitem_order
menuitem_name
menuitem_page_id
parent_menuitem_id
I do get this output as a hierarchical tree, but that isn't the desired format for storing it into my database:
Array
(
[0] => Array
(
[id] => 2
)
[1] => Array
(
[id] => 1
[children] => Array
(
[0] => Array
(
[id] => 3
[children] => Array
(
[0] => Array
(
[id] => 4
)
[1] => Array
(
[id] => 5
)
)
)
[1] => Array
(
[id] => 6
)
)
)
)
However, I want to convert this to a parent ID array with new fresh ID's (I will truncate the table and insert new data). Something like this:
Array
(
[0] => 0
[1] => 0
[2] => 2
[3] => 3
[4] => 3
[5] => 2
)
How can this be done?
Note: i have read this article, but I need the opposite code of it.

Answer 1

You need a recursive function:
function flattenHierarchicalArray($arr, $parentId = null) {
$items = array();
foreach ($arr as $item) {
$items[] = array('id' => $item['id'], 'parentId' = $parentId);
if (isset($item['children'])) $items = array_merge($items, flattenHierarchicalArray($item['children'], $item['id']));
}
return $items;
}

Answer 2

I think I have the solution combined with AlliterativeAlice's PHP code.
I'm using the Nestable plugin. That extension creates my hierarchical tree and sets it in a hidden field in my form (done by JavaScript). I updated this code to create new IDs by adding this code:
var nestable_update = function(e){
//added for updating old IDs
$(".dd-item").each(function(index){
$(this).data("id", index+1);
});
var list = e.length ? e : $(e.target),
output = list.data("output");
if (window.JSON) {
output.val(window.JSON.stringify(list.nestable("serialize")));
} else {
output.val("JSON browser support required for this demo.");
}
};
$(".dd").nestable({
maxDepth:5
}).on("change", nestable_update);
nestable_update($(".dd").data("output", $("#nestable_output")));
I used your PHP code for getting the parentID (many thanks to AlliterativeAlice, because it's more efficient than my original PHP code):
function flatten_hierarchical_tree($arr, $parent_id=0) {
$items = array();
foreach ($arr as $item) {
$items[] = array('id' => $item['id'], 'parent_id' => $parent_id);
if (isset($item['children'])) $items = array_merge($items, flatten_hierarchical_tree($item['children'], $item['id']));
}
return $items;
}

Answer 3

For those who are interested in my final code. It works for storing the data in the database and build it again into a hierarchical tree + a printable tree for HTML.
JavaScript code for the nestable plugin:
var nestable_update = function(e){
$(".dd-item").each(function(index){
$(this).data("id", index+1);
});
var list = e.length ? e : $(e.target),
output = list.data("output");
if (window.JSON) {
output.val(window.JSON.stringify(list.nestable("serialize")));
} else {
output.val("JSON browser support required for this demo.");
}
};
$(".dd").nestable({
maxDepth:5
}).on("change", nestable_update);
nestable_update($(".dd").data("output", $("#nestable_output")));
Database structure:
menuitem_id
menu_id
menuitem_order
menuitem_name
menuitem_page_id
parent_menuitem_id
PHP functions for building trees (format storing data in database + format getting data from database):
function create_flatten_hierarchical_tree($tree, $parent_id=0) {
$items = array();
foreach ($tree as $item) {
$items[] = array("id" => $item["id"], "parent_id" => $parent_id);
if (isset($item["children"])) $items = array_merge($items, create_flatten_hierarchical_tree($item["children"], $item["id"]));
}
return $items;
}
function create_hierarchical_tree($tree, $root=0) {
$return = array();
foreach($tree as $child => $parent) {
if($parent["parent_menuitem_id"] == $root) {
if(isset($tree[$child]["menuitem_id"]) === true){
$parent['children'] = create_hierarchical_tree($tree, $tree[$child]["menuitem_id"]);
}
unset($tree[$child]);
$return[] = $parent;
}
}
return empty($return) ? null : $return;
}
function print_hierarchical_tree($tree, $rows_pages) {
if(!is_null($tree) && count($tree) > 0) {
$return .= "<ol class='dd-list'>";
foreach($tree as $item){
$options = "";
foreach($rows_pages as $row_pages){
$selected = "";
if($row_pages["page_id"] == $item["menuitem_page_id"]){
$selected = "selected";
}
$options .= "<option value='".$row_pages["page_id"]."' $selected>".$row_pages["friendly_url"]."</option>";
}
$return .= "<li class='dd-item' data-id='".$item["menuitem_id"]."'><div class='dd-handle'>drag</div><div class='item_wrapper'><div class='item'><div class='item_title'>".$item["menuitem_name"]."</div></div><div class='item_sub'><div class='label_input'><label for='menuitem_name".$item["menuitem_id"]."'>Menuitem name</label><input type='text' id='menuitem_name".$item["menuitem_id"]."' name='menuitem_name[]' value='".$item["menuitem_name"]."' /></div><div class='label_input'><label for='page_link".$item["menuitem_id"]."'>Page link</label><label class='select'><select id='page_link".$item["menuitem_id"]."' name='menuitem_page_id[]'>".$options."</select></label></div> <a onClick='delete_menuitem(".$item["menuitem_id"].");' class='button red_bg delete'>Delete</a></div></div>";
$return .= print_hierarchical_tree($item["children"], $rows_pages);
$return .= "</li>";
}
$return .= "</ol>";
}
return empty($return) ? null : $return;
}
Core code of menu_edit.php page:
<?php
$stmt_menuitems = $dbh->prepare("SELECT * FROM inno_mw_thurs_menuitems mi WHERE mi.menu_id=:menu_id");
$stmt_menuitems->bindParam(":menu_id", $_GET["menu_id"]);
$stmt_menuitems->execute();
if (!empty($stmt_menuitems->rowCount())) {
?>
<div class="dd">
<?php
$result = $stmt_menuitems->fetchAll();
$tree = create_hierarchical_tree($result);
$stmt_pages = $dbh->prepare("SELECT * FROM inno_mw_thurs_pages");
$stmt_pages->execute();
$rows_pages = $stmt_pages->fetchAll();
$tree = print_hierarchical_tree($tree, $rows_pages);
echo $tree;
?>
</div>
<?php
}
Core code of menu_edit_process.php page:
if(isset($_POST["menu_id"])){
$menu_id = $_POST["menu_id"];
$nestable_output = json_decode($_POST["nestable_output"], true);
$parent_menuitem_ids_arr = create_flatten_hierarchical_tree($nestable_output);
$stmt = $dbh->prepare("TRUNCATE TABLE inno_mw_thurs_menuitems");
$stmt->execute();
$stmt = $dbh->prepare("INSERT INTO inno_mw_thurs_menuitems (menu_id, menuitem_order, menuitem_name, menuitem_page_id, parent_menuitem_id) VALUES (:menu_id, :menuitem_order, :menuitem_name, :menuitem_page_id, :parent_menuitem_id)");
$menuitem_order_arr = array();
foreach($_POST["menuitem_name"] as $f => $name){
$menuitem_name = $_POST["menuitem_name"][$f];
$menuitem_page_id = $_POST["menuitem_page_id"][$f];
$parent_menuitem_id = $parent_menuitem_ids_arr[$f]["parent_id"];
if(array_key_exists($parent_menuitem_id, $menuitem_order_arr) && $parent_menuitem_id != 0){
$menuitem_order_arr[$parent_menuitem_id] += 1;
}
else{
$menuitem_order_arr[$parent_menuitem_id] = 0;
}
$stmt->bindParam(":menu_id", $menu_id);
$stmt->bindParam(":menuitem_order", $menuitem_order_arr[$parent_menuitem_id]);
$stmt->bindParam(":menuitem_name", $menuitem_name);
$stmt->bindParam(":menuitem_page_id", $menuitem_page_id);
$stmt->bindParam(":parent_menuitem_id", $parent_menuitem_id);
$stmt->execute();
}
header("location: menus_list.php");
}
Please, feel free to improve this code.