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What are UUIDs?

UUID stands for Universal Unique Identifier. It's a 128-bit number used to uniquely identify some object or in our case, a record in our database.

I won't go into depth about the pros or cons of UUIDs when compared to a regular auto incrementing ID, that's an entire blog post of its own. What I will do, is show you how easy it is to use UUIDs in your Laravel application if you wish too.

Prepare your migration

The first step of using UUIDs in your database is setting up your column to be of a specific type. By default, a Laravel migration includes a $table->primary('id'); column in each migration you create.

Using UUIDs is as simple as updating our migration to use the ->uuid() method that Laravel provides out of the box for us. For example, let's say we're creating a migration to describe the schema of a Post.

Schema::create('posts', function (Blueprint $table) {
    $table->uuid('id')->primary();
    $table->string('title');
    $table->text('body');
    $table->timestamps();
});

The important line you should notice is this one: $table->uuid('id')->primary();. Notice we are using the uuid() method instead of the common increments() method. As you can see, the uuid() method specifies the column should be a UUID equivalent column and we also specify that it should be the primary key on the table.

Creating the UUID

If you run php artisan migrate, and try to create a new record using something like a factory, or manually creating it, you'll run into an error saying the id column cannot be null.

When using the primary() method on our migrations, Laravel will notice it's an auto-incrementing column and whip it up for us. But, since we switched over to using UUIDs, we'll need to create the ID ourselves.

Use Eloquent Model Events

Since you're using Laravel, I imagine you would also be using Eloquent to easily interact with your database.

Eloquent has what are known as Model Events. In total, it fires a total of 11 events in different scenarios. You have the following events:

  • retrieved
  • creating
  • created
  • updating
  • updated
  • saving
  • saved
  • deleting
  • deleted
  • restoring
  • restored.

If you want to learn more about Eloquent Events, you can find their documentation here.

Now, back to creating our UUIDs. Let's take a look at how your Post model could look like:

class Post extends Model
{
    protected $guarded = []; // YOLO

    protected static function boot()
    {
        parent::boot();

        static::creating(function ($post) {
            $post->{$post->getKeyName()} = (string) Str::uuid();
        });
    }

    public function getIncrementing()
    {
        return false;
    }

    public function getKeyType()
    {
        return 'string';
    }
}

Our Model has 3 methods in it. The boot method is where we can hook into our model and listen for any Eloquent events. The getIncrementing method is used by Eloquent to now if the IDs on the table are incrementing. Remember we are using UUIDs so we set auto incrementing to false. Lastly, the getKeyType method just specifies that the IDs on the table should be stored as strings.

In our boot method, we are listening for the creating Eloquent event. This even is fired just before the record is actually stored in the database. We hook into this event, and use the uuid() method provided by the Str class in Laravel.

A while ago, people might have installed a package with Composer in order to generate a UUID but you can generate them easily using the uuid() method provided by the class.

Easy as that, you can use UUIDs in Laravel.

As I final note, I'll usually have a PHP trait called UsesUuid where I'll have the logic above. That way I wouldn't repeated the code on every model I wanted to use UUIDs.

This is what the UsesUuid trait would look like:

<?php

namespace App\Models\Concerns;

use Illuminate\Support\Str;

trait UsesUuid
{
    protected static function bootUsesUuid()
    {
        static::creating(function ($model) {
            if (! $model->getKey()) {
                $model->{$model->getKeyName()} = (string) Str::uuid();
            }
        });
    }

    public function getIncrementing()
    {
        return false;
    }

    public function getKeyType()
    {
        return 'string';
    }
}

Notice how everything is more generalized and not tied to a unique model.

Now, in any model that as the correct column in its migration you can simply use the UsesUuid trait like so:

class Post extends Model
{
  use App\Models\Concerns\UsesUuid;

  protected $guarded = []; // YOLO
}

That's it. In just a few simple steps you got UUIDs working in your Laravel app.

Published on: Oct 29, 2018

Tags: php laravel uuids

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