Hierarchia kategorii (PHP / MySQL)

Mam nowy pomysł, myślę, że będzie miło. Chodzi o to, że: w kolumnie category_parent wstawimy odniesienie do wszystkich rodziców tego węzła.

+----+----------------------+-----------------+
| id | category_name        |    hierarchy    |
+----+----------------------+-----------------+
| 1  | cat1                 |        1        |
+----+----------------------+-----------------+
| 2  | cat2                 |        2        |
+----+----------------------+-----------------+
| 3  | cat3                 |        3        |
+----+----------------------+-----------------+
| 4  | subcat1_1            |       1-4       |
+----+----------------------+-----------------+
| 5  | subcat1_2            |       1-5       |
+----+----------------------+-----------------+
| 6  | subsubcat1_1         |      1-4-6      |
+----+----------------------+-----------------+
| 7  | subsubcat1_2         |      1-4-7      |
+----+----------------------+-----------------+
| 8  | subsubcat1_3         |      1-4-8      |
+----+----------------------+-----------------+
| 9  | subsubcat1_3_1       |     1-4-8-9     |
+----+----------------------+-----------------+
| 10 | subsubcat1_3_2       |     1-4-8-10    |
+----+----------------------+-----------------+
| 11 | subsubcat1_3_1_1     |    1-4-8-9-11   |
+----+----------------------+-----------------+
| 12 | subsubsubcat1_3_1_1  |   1-4-8-9-12    |
+----+----------------------+-----------------+
| 13 | subsubsubcat1_3_1_2  |  1-4-8-9-11-13  |
+----+----------------------+-----------------+
| 14 | subsubsubcat1_2_1_3  |  1-4-8-9-11-14  |
+----+----------------------+-----------------+

Jeśli spojrzysz na moją zaktualizowaną tabelę, zauważysz, że każdy rekord ma link do swoich rodziców, nie tylko bezpośredni, ale także wszystkich rodziców. A do tego zadania zrobiłem jakąś modyfikację do wstawienia do be:

Insert into table_name (category_name, hierarchy) values ('new_name', (concat(parent_hierarch, '-', (SELECT Auto_increment FROM information_schema.tables WHERE table_name='table_name'))))

Teraz pozwala dokonać żądanych zapytań:

1-wszystkie podkategorie samochodów:

select * from table_name where hierarchy like '1-%'

2-jeśli need all parent of BLACK wystarczy wpisać:

select * from table_name where hierarchy = '1-4-8-9' or hierarchy = '1-4-8' or hierarchy = '1-4' or hierarchy = '1'

(możesz zbudować to zapytanie z php, dzieląc pole hierarchii na znak' -')

3 - aby zobaczyć wszystkie kategorie, z nadrzędnym poziomem i bezpośrednim:

select *, SUBSTR(hierarchy, 1, (LENGTH(hierarchy) - LENGTH(id) - 1)) as parent, LENGTH(hierarchy) - LENGTH(REPLACE(hierarchy, '-', '')) as level From table_name

+----+----------------------+-----------------+-----------+--------+
| id | category name        |    hierarchy    |   parent  |  level |
+----+----------------------+-----------------+-----------+--------+
| 1  | cat1                 |        1        |           |    0   |
+----+----------------------+-----------------+-----------+--------+
| 2  | cat2                 |        2        |           |    0   |
+----+----------------------+-----------------+-----------+--------+
| 3  | cat3                 |        3        |           |    0   |
+----+----------------------+-----------------+-----------+--------+
| 4  | subcat1_1            |       1-4       |     1     |    1   |
+----+----------------------+-----------------+-----------+--------+
| 5  | subcat1_2            |       1-5       |     1     |    1   |
+----+----------------------+-----------------+-----------+--------+
| 6  | subsubcat1_1         |      1-4-6      |    1-4    |    2   |
+----+----------------------+-----------------+-----------+--------+
| 7  | subsubcat1_2         |      1-4-7      |    1-4    |    2   |
+----+----------------------+-----------------+-----------+--------+
| 8  | subsubcat1_3         |      1-4-8      |    1-4    |    2   |
+----+----------------------+-----------------+-----------+--------+
| 9  | subsubcat1_3_1       |     1-4-8-9     |   1-4-8   |    3   |
+----+----------------------+-----------------+-----------+--------+
| 10 | subsubcat1_3_2       |     1-4-8-10    |   1-4-8   |    3   |
+----+----------------------+-----------------+-----------+--------+
| 11 | subsubcat1_3_1_1     |    1-4-8-9-11   |  1-4-8-9  |    4   |
+----+----------------------+-----------------+-----------+--------+
| 12 | subsubsubcat1_3_1_1  |   1-4-8-9-12    |  1-4-8-9  |    4   |
+----+----------------------+-----------------+-----------+--------+
| 13 | subsubsubcat1_3_1_2  |  1-4-8-9-11-13  |1-4-8-9-11 |    5   |
+----+----------------------+-----------------+-----------+--------+
| 14 | subsubsubcat1_2_1_3  |  1-4-8-9-11-14  |1-4-8-9-11 |    5   |
+----+----------------------+-----------------+-----------+--------+

@Amnon Twój kod działa idealnie. Po prostu Przetestowałem go za pomocą CodeIgniter i zadziałało jak urok. Oto działający kod, jeśli ktoś go potrzebuje:

<?php

function disTree($all_cats) {
$tree = array();
foreach ($all_cats as $cat)
{
    $pid  = $cat->parent_id;
    $id   = $cat->cat_id;
    $name = $cat->cat_name;

    // Create or add child information to the parent node
    if (isset($tree[$pid]))
        // a node for the parent exists
        // add another child id to this parent
        $tree[$pid]["children"][] = $id;
    else
        // create the first child to this parent
        $tree[$pid] = array("children"=>array($id));

    // Create or add name information for current node
    if (isset($tree[$id]))
        // a node for the id exists:
        // set the name of current node
        $tree[$id]["name"] = $name;
    else
        // create the current node and give it a name
        $tree[$id] = array( "name"=>$name );
}
return $tree;
}


function toUL($tree, $id, $html){
  $html .= '<ul>'.PHP_EOL;

  if (isset($tree[$id]['name']))
    $html .= '<li>' . $tree[$id]['name'];

  if (isset($tree[$id]['children']))
  {
    $arChildren = &$tree[$id]['children'];
    $len = count($arChildren);
    for ($i=0; $i<$len; $i++) {
        $html .= toUL($tree, $arChildren[$i], "");
    }
    $html .= '</li>'.PHP_EOL;
  }

  $html .= '</ul>'.PHP_EOL;
  return $html;
}

$tree = disTree($all_cats);
// Display the tree
echo toUL($tree, 0, "");

?>

Jedyną rzeczą, którą zmieniłem było dodanie własnej tablicy ($all_cats).

Wypróbuj następujący kod

//Połącz się z mysql i wybierz db

$conn = mysqli_connect('localhost', 'user', 'password','database');

if( !empty($conn->connect_errno)) die("Error " . mysqli_error($conn));

//call the recursive function to print category listing
category_tree(0);

//Recursive php function
function category_tree($catid){
global $conn;

$sql = "select * from category where parent_id ='".$catid."'";
$result = $conn->query($sql);

while($row = mysqli_fetch_object($result)):
$i = 0;
if ($i == 0) echo '<ul>';
 echo '<li>' . $row->cat_name;
 category_tree($row->id);
 echo '</li>';
$i++;
 if ($i > 0) echo '</ul>';
endwhile;
}
//close the connection
mysqli_close($conn);
?>

Więcej...

Jest inny sposób na osiągnięcie tego samego efektu, który uważam za nieco łatwiejszy do naśladowania (bez triku referencyjnego). Tworzysz drzewo dodając odpowiednie informacje do bieżącego węzła i do jego rodzica (Załóżmy, że foreach iteruje nad zwracanymi wierszami z zapytania SQL):

$tree = array();
foreach ($query->result() as $row)
{
    $pid  = $row->parent_id;
    $id   = $row->id;
    $name = $row->name;

    // Create or add child information to the parent node
    if (isset($tree[$pid]))
        // a node for the parent exists
        // add another child id to this parent
        $tree[$pid]["children"][] = $id;
    else
        // create the first child to this parent
        $tree[$pid] = array("children"=>array($id));

    // Create or add name information for current node
    if (isset($tree[$id]))
        // a node for the id exists:
        // set the name of current node
        $tree[$id]["name"] = $name;
    else
        // create the current node and give it a name
        $tree[$id] = array( "name"=>$name );
}
return $tree;

I wyświetlenie drzewa:

function toUL($tree, $id, $html){
  $html .= '<ul>'.PHP_EOL;

  if (isset($tree[$id]['name']))
    $html .= '<li>' . $tree[$id]['name'];

  if (isset($tree[$id]['children']))
  {
    $arChildren = &$tree[$id]['children'];
    $len = count($arChildren);
    for ($i=0; $i<$len; $i++) {
        $html .= toUL($tree, $arChildren[$i], "");
    }
    $html .= '</li>'.PHP_EOL;
  }

  $html .= '</ul>'.PHP_EOL;
  return $html;
}

// Display the tree
echo toUL($tree, 0, "");