Laravel Transferable Model Relationships

Make laravel model relationships transferable!

This is perfect to use when you want a model relationships to me assigned to another model (of the same type) and not be deleted or set null.

Install

composer require nhalstead/transferable

How to use

On the model its self you need to add in the use statement and optionally add in the implements to block the model from being deleted.

<?php

namespace App\Models;

use nhalstead\Transferable\Interfaces\NoDanglingRelationships;
use nhalstead\Transferable\Traits\TransferableRelationship;
use Illuminate\Database\Eloquent\Model;

class User extends Model implements NoDanglingRelationships
{
	use TransferableRelationship;

	protected $transferable = [
		"items"
	];

	public function items()
	{
		return $this->hasMany(Items::class);
	}
  
}

By attaching the interface NoDanglingRelationships you enable checks before deletion to ensure no relationships are connected that could be transferred.

What now?

We're able to block delete actions if we have relationships that can be transferred still attached, what now?

This package provides a few extra functions to all models that use TransferableRelationship to make things easy and efficient. If a model wants to transfer its relationships to another model you can use the example below:

<?php

$oldUser = User::find(1);
$newUser = User::find(2);

// Doing `delete()` will trigger an exception so you need
//  to transfer any items that are connected to another model.

// Transfer relationships to another item.
$oldUser->transferTo($newUser); // Returns the total rows changed.

// Bob's your uncle, now oldUser can be deleted.
$oldUser->delete();

?>

What makes it efficient? This will use the model's relationship to determine what needs to be updated in the database and runs a query on the DB to update the relationships without any extra calls to get all the IDs and detaching things.

What else?

Nothing else, This package offers a few extra method for debugging and collecting information on the transferable relationships, see below:

// Return the number of transferable items attached to this model
$newUser->countTransferable();

// Return boolean if it would have any dangling relationships if deleted.
// The false param tells it not to throw an Exception
$newUser->checkDangling(false);