README

The nested set model is an advanced technique for maintaining hierachies among models using parent_id, nest_left, nest_right, and nest_depth columns. To use a nested set model, apply the ArtisanWebLab\NestedTree\Database\Traits\NestedTreeTrait trait.

composer require artisanweblab/nested-tree

 $table->integer('parent_id')->nullable();
 $table->integer('nest_left')->nullable();
 $table->integer('nest_right')->nullable();
 $table->integer('nest_depth')->nullable();

use ArtisanWebLab\NestedTree\Database\Traits\NestedTreeTrait;

class Category extends Model
{
    use NestedTreeTrait;

    // You can change the column names used by declaring    
    const PARENT_ID = 'my_parent_column';
    const NEST_LEFT = 'my_left_column';
    const NEST_RIGHT = 'my_right_column';
    const NEST_DEPTH = 'my_depth_column';
}

Creating a root node

By default, all nodes are created as roots:

$root = Category::create(['name' => 'Root category']);

Alternatively, you may find yourself in the need of converting an existing node into a root node:

$node->makeRoot();

You may also nullify it's parent_id column which works the same as `makeRoot'.

$node->parent_id = null;
$node->save();

Inserting nodes

You can insert new nodes directly by the relation:

$child1 = $root->children()->create(['name' => 'Child 1']);

Or use the makeChildOf method for existing nodes:

$child2 = Category::create(['name' => 'Child 2']);
$child2->makeChildOf($root);

Deleting nodes

When a node is deleted with the delete method, all descendants of the node will also be deleted. Note that the delete model events will not be fired for the child models.

$child1->delete();

Getting the nesting level of a node

The getLevel method will return current nesting level, or depth, of a node.

// 0 when root
$node->getLevel()

Moving nodes around

There are several methods for moving nodes around:

• moveLeft(): Find the left sibling and move to the left of it.
• moveRight(): Find the right sibling and move to the right of it.
• moveBefore($otherNode): Move to the node to the left of ...
• moveAfter($otherNode): Move to the node to the right of ...
• makeChildOf($otherNode): Make the node a child of ...
• makeRoot(): Make current node a root node.

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