Yii2 Adjacency List Behavior

Implementation of adjacency list algorithm for storing the trees in DB tables.

Install

Install via Composer:

composer require paulzi/yii2-adjacency-list

or add

"paulzi/yii2-adjacency-list" : "^2.2"

to the require section of your composer.json file.

Migrations example

class m150722_150000_adjacency_list extends Migration
{
    public function up()
    {
        $tableOptions = null;
        if ($this->db->driverName === 'mysql') {
            // http://stackoverflow.com/questions/766809/whats-the-difference-between-utf8-general-ci-and-utf8-unicode-ci
            $tableOptions = 'CHARACTER SET utf8 COLLATE utf8_unicode_ci ENGINE=InnoDB';
        }
        $this->createTable('{{%adjacency_list}}', [
            'id'        => Schema::TYPE_PK,
            'parent_id' => Schema::TYPE_INTEGER . ' NULL',
            'sort'      => Schema::TYPE_INTEGER . ' NOT NULL',
            'name'      => Schema::TYPE_STRING . ' NOT NULL', // example field
        ], $tableOptions);
        $this->createIndex('parent_sort', '{{%adjacency_list}}', ['parent_id', 'sort']);
    }
}

Configuring

use paulzi\adjacencyList\AdjacencyListBehavior;

class Sample extends \yii\db\ActiveRecord
{
    public function behaviors() {
        return [
            [
                'class' => AdjacencyListBehavior::className(),
            ],
        ];
    }
}

Optional you can setup Query for finding roots:

class Sample extends \yii\db\ActiveRecord
{
    public static function find()
    {
        return new SampleQuery(get_called_class());
    }
}

Query class:

use paulzi\adjacencyList\AdjacencyListQueryTrait;

class SampleQuery extends \yii\db\ActiveQuery
{
    use AdjacencyListQueryTrait;
}

Sortable Behavior

This behavior attach SortableBehavior. You can use its methods (for example, reorder()).

Options

• $parentAttribute = 'parent_id' - parent attribute in table schema.
• $sortable = [] - SortableBehavior settings - see paulzi/yii2-sortable.
• $checkLoop = false - check loop when moving nodes (slower).
• $parentsJoinLevels = 3 - amount of join levels, when finding ancestors.
• $childrenJoinLevels = 3 - amount of join levels, when finding descendants.

Usage

Selection

Getting the root nodes

If you connect AdjacencyListQueryTrait, you can get all the root nodes:

$roots = Sample::find()->roots()->all();

Getting ancestors of a node

To get ancestors of a node:

$node11 = Sample::findOne(['name' => 'node 1.1']);
$parents = $node11->parents; // via relation unsorted
$parents = $node11->parentsOrdered; // via relation sorted
$parents = $node11->getParents()->all(); // via query
$parents = $node11->getParents(2)->all(); // get 2 levels of ancestors

To get parent of a node:

$node11 = Sample::findOne(['name' => 'node 1.1']);
$parent = $node11->parent; // via relation
$parent = $node11->getParent()->one(); // via query

To get root of a node:

$node11 = Sample::findOne(['name' => 'node 1.1']);
$root = $node11->root; // via relation
$root = $node11->getRoot()->one(); // via query

For get ordered list of primary keys ancestors:

$node11 = Sample::findOne(['name' => 'node 1.1']);
$ids = $node11->getParentsIds();
$ids = $node11->getParentsIds(3, false); // get 3 levels of ancestors primary keys with force updating from DB 

Getting descendants of a node

To get all the descendants of a node:

$node11 = Sample::findOne(['name' => 'node 1.1']);
$descendants = $node11->descendants; // via relation unsorted
$descendants = $node11->descendantsOrdered; // via relation sorted
$descendants = $node11->getDescendants()->all(); // via query
$descendants = $node11->getDescendants(2, true)->all(); // get 2 levels of descendants and self node

*Note: guaranteed order on each parent nodes, nodes of different parents can be mixed with each other and option childrenJoinLevels can change this order.

To populate children relations for self and descendants of a node:

$node11 = Sample::findOne(['name' => 'node 1.1']);
$tree = $node11->populateTree(); // populate all levels
$tree = $node11->populateTree(2); // populate 2 levels of descendants

To get the children of a node:

$node11 = Sample::findOne(['name' => 'node 1.1']);
$children = $node11->children; // via relation
$children = $node11->getChildren()->all(); // via query

For get ordered array of primary keys descendants per level:

$node11 = Sample::findOne(['name' => 'node 1.1']);
$ids = $node11->getDescendantsIds(); // get array of per-level descendants primary keys
$ids = $node11->getDescendantsIds(null, true); // get flat array of descendants primary keys
$ids = $node11->getDescendantsIds(3, false, false); // get 3 levels array of per-level descendants primary keys with force updating from DB 

*Note: guaranteed order on each parent nodes, nodes of different parents can be mixed with each other and option childrenJoinLevels can change this order.

Getting the leaves nodes

To get all the leaves of a node:

$node11 = Sample::findOne(['name' => 'node 1.1']);
$leaves = $node11->leaves; // via relation
$leaves = $node11->getLeaves(2)->all(); // get 2 levels of leaves via query

Getting the neighbors nodes

To get the next node:

$node11 = Sample::findOne(['name' => 'node 1.1']);
$next = $node11->next; // via relation
$next = $node11->getNext()->one(); // via query

To get the previous node:

$node11 = Sample::findOne(['name' => 'node 1.1']);
$prev = $node11->prev; // via relation
$prev = $node11->getPrev()->one(); // via query

Some checks

$node1 = Sample::findOne(['name' => 'node 1']);
$node11 = Sample::findOne(['name' => 'node 1.1']);
$node11->isRoot() - return true, if node is root
$node11->isLeaf() - return true, if node is leaf
$node11->isChildOf($node1) - return true, if node11 is child of $node1

Modifications

To make a root node:

$node11 = new Sample();
$node11->name = 'node 1.1';
$node11->makeRoot()->save();

Note: if you allow multiple trees and attribute tree is not set, it automatically takes the primary key value.

To prepend a node as the first child of another node:

$node1 = Sample::findOne(['name' => 'node 1']);
$node11 = new Sample();
$node11->name = 'node 1.1';
$node11->prependTo($node1)->save(); // inserting new node

To append a node as the last child of another node:

$node11 = Sample::findOne(['name' => 'node 1.1']);
$node12 = Sample::findOne(['name' => 'node 1.2']);
$node12->appendTo($node11)->save(); // move existing node

To insert a node before another node:

$node13 = Sample::findOne(['name' => 'node 1.3']);
$node12 = new Sample();
$node12->name = 'node 1.2';
$node12->insertBefore($node13)->save(); // inserting new node

To insert a node after another node:

$node13 = Sample::findOne(['name' => 'node 1.3']);
$node14 = Sample::findOne(['name' => 'node 1.4']);
$node14->insertAfter($node13)->save(); // move existing node

To delete a node with descendants:

$node11 = Sample::findOne(['name' => 'node 1.1']);
$node11->delete(); // delete node, children come up to the parent
$node11->deleteWithChildren(); // delete node and all descendants 

Note: when deleting with delete() child nodes mixed with parent

Reorder children:

$model = Sample::findOne(1);
$model->reorderChildren(true); // reorder with center zero
$model = Sample::findOne(2);
$model->reorderChildren(false); // reorder from zero

Updating from 1.x to 2.x

1. Move attributes sortAttribute, step into sortable attribute.
2. Change namespace from paulzi\adjacencylist to paulzi\adjacencyList.
3. Include paulzi\yii2-sortable (composer update).