Node

The model traits can implement functionality. The node in the design can be divided into Simple Tree as well as a Nested Tree

Simple Tree

A simple tree model will use the parent_id column maintain a parent and child relationship between models. To use the simple tree, apply the Litepie\Node\Traits\SimpleTree trait.

	class Category extends Model
	{
	    use \Litepie\Node\Traits\SimpleTree;
	}

This trait will automatically inject two model relations called parent and children**, it is the equivalent of the following definitions.

	public $belongsTo = [
	    'parent'    => ['User', 'key' => 'parent_id'],
	];

	public $hasMany = [
	    'children'    => ['User', 'key' => 'parent_id'],
	];

You can further go onto modifying the respective key name that has been used to identify the parent by defining the parent_id variable:

var paretn_id = 'parent_id';

Collections of models that use this trait will return the type of \Litepie\Node\NodeCollection which adds the toNested method. To build an eager loaded tree structure, return the records with the relations eager loaded.

Category::all()->toNested();

Nested Tree

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 \Litepie\Node\Traits\NestedTree trait. All of the features of the SimpleTree trait are inherently available in this model.

	class Category extends Model
	{
	    use \Litepie\Node\Traits\NestedNode;
	}

##Creating a root node## The default action of the compiler is to create all nodes as root nodes.

$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:

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

##Deleting Nodes## When a particular 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##

You can identify the level at which the node is embedded. 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. You could implement them through the following code

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 a defined node

moveAfter($otherNode): Move to the node to the right of a defined node

makeChildOf($otherNode): Make the node a child of a defined node

makeRoot(): Make current node a root node.