Seeding Table with Relationships in Laravel

18 March 2018

This is my answer to someone’s question on StackOverflow. How can we seed table with relationships in Laravel? Let’s learn how to define relationships on the Eloquent model and use Laravel’s model factory to seed the database.

Model and Table Structure

Before getting started, let me explain the context of the question. Let’s say we have a Customer model. This model has two relationships to other tables. First, it has a one-to-one relationship with CustomerAddress model—it means a single customer only has one address. The second relationship is one-to-many with CustomerPurchase model—it means a single customer may have multiple purchase records.

Let’s briefly explore our model schemas.

Customer Model

The Customer model is a representation of the customers table. It has five columns: id, name, phone, created_at, and updated_at. The migration file might look something like this:

// Within the migration file for creating customers table.
Schema::create('customers', function (Blueprint $table) {
    $table->increments('id');
    $table->string('name');
    $table->string('phone');
    $table->timestamps();
});

And the model class stored in app/Customer.php looks like this:

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Customer extends Model
{
    protected $fillable = ['name', 'phone'];
}

Customer Address Model

The CustomerAddress model represents the customer’s address. It uses the customer_addresses table with eight columns on it: id, customer_id, address, city, state, zip, created_at, and updated_at. The migration file looks like this:

// Within the migration file for creating customer_addresses table.
Schema::create('customer_addresses', function (Blueprint $table) {
    $table->increments('id');
    $table->integer('customer_id')->unsigned();
    $table->foreign('customer_id')->references('id')->on('customers');
    $table->string('address');
    $table->string('city');
    $table->char('state', 2);
    $table->char('zip', 5);
    $table->timestamps();
});

The model class itself stored in app/CustomerAddress.php and it looks like this:

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class CustomerAddress extends Model
{
    protected $fillable = ['address', 'city', 'state', 'zip'];
}

Customer Purchase Model

Finally, the CustomerPurchase represents the customer_addresses table. It has six columns: id, customer_id, method, amount, created_at, and updated_at. Its migration file looks like this:

// Within the migration file for creating customer_addresses table.
Schema::create('customer_purchases', function (Blueprint $table) {
    $table->increments('id');
    $table->integer('customer_id')->unsigned();
    $table->foreign('customer_id')->references('id')->on('customers');
    $table->enum('method', ['credit_card', 'paypal']);
    $table->decimal('amount', 8, 2);
    $table->timestamps();
});

The model saved in app/CustomerPurchase.php and it looks like this:

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class CustomerPurchase extends Model
{
    const METHOD_CREDIT_CARD = 'credit_card';
    const METHOD_PAYPAL = 'paypal';

    protected $fillable = ['method', 'amount'];
}

Defining Relationships

Our first step to solve this problem is to define the relationships between these three models. Let’s open our Customer model and define its relationships both with CustomerAddress and CustomerPurchase models.

class Customer extends Model
{
    // Omitted for brevity

    public function address()
    {
        return $this->hasOne(CustomerAddress::class);
    }

    public function purchases()
    {
        return $this->hasMany(CustomerPurchase::class);
    }
}

For the one-to-one relationship with CustomerAddress, we use the hasOne() method. While for the one-to-many relationship with CustomerPurchase we use the hasMany() method.

Note that we use singular form for a method name that defines one-to-one relationship: address(). And use the plural form for a method name that defines one-to-many relationship: purchases(). We also omit the customer part, since it’s redundant inside the Customer class. This way, we’ll have a clean and readable API:

$customer = App\Customer::find(1);

$customer->address;

$customer->purchases->sortBy('amount');

Defining Inverse Relationships

For this tutorial, it’s not required to define the inverse relationships. But let’s go ahead and define the relationship between CustomerAddress and CustomerPurchase models:

class CustomerAddress extends Model
{
    // Omitted for brevity

    public function customer()
    {
        return $this->belongsTo(Customer::class);
    }
}

We also define the identical customer() method within the CustomerPurchase model:

class CustomerPurchase extends Model
{
    // Omitted for brevity

    public function customer()
    {
        return $this->belongsTo(Customer::class);
    }
}

The Model Factory

Next, we’re going to need to write a model factory for each of our models. We can generate a model factory through artisan command. Open our your terminal and type the following command within your Laravel’s project directory:

$ php artisan make:factory CustomerFactory

This will create a new file in app\database\factories\CustomerFactory.php. We can have a separate file for each of our model or we can just write all of the model factories code within this single file. Open up the CustomerFactory.php file and define the model factory for our three models:

<?php

use App\Customer;
use App\CustomerAddress;
use App\CustomerPurchase;
use Faker\Generator as Faker;

$factory->define(Customer::class, function (Faker $faker) {
    return [
        'name' => $faker->name,
        'phone' => $faker->phoneNumber,
    ];
});

$factory->define(CustomerAddress::class, function (Faker $faker) {
    return [
        'address' => $faker->streetAddress,
        'city' => $faker->city,
        'state' => $faker->stateAbbr,
        'zip' => $faker->postcode,
    ];
});

$factory->define(CustomerPurchase::class, function (Faker $faker) {
    return [
        'method' => $faker->randomElement([
            CustomerPurchase::METHOD_CREDIT_CARD,
            CustomerPurchase::METHOD_PAYPAL,
        ]),
        'amount' => $faker->randomFloat(2, 10, 200),
    ];
});

By default, Laravel provides us with Faker library that we can use to generate a random data.

On model factory for CustomerPurchase, we use randomElement method. It will simply pick a single item from the given array. On our case, we passed the METHOD_CREDIT_CARD and METHOD_PAYPAL constants, so it will randomly return a string either credit_card or paypal.

Database Seeding with Model Factory

Our model’s relationships are set and the model factories are ready to use. We can now seed our database!

We can create a separate class for our seeder. But let’s keep it simple and write the code to the database\seeds\DatabaseSeeder.php file:

<?php

use Illuminate\Database\Seeder;

class DatabaseSeeder extends Seeder
{
    public function run()
    {
        // Create 10 records of customers
        factory(App\Customer::class, 10)->create()->each(function ($customer) {
            // Seed the relation with one address
            $address = factory(App\CustomerAddress::class)->make();
            $customer->address()->save($address);

            // Seed the relation with 5 purchases
            $purchases = factory(App\CustomerPurchase::class, 5)->make();
            $customer->purchases()->saveMany($purchases);
        });
    }
}

First, we created 10 customers with random data. Then we loop through the created model’s collection with each method.

factory(App\Customer::class, 10)->create()->each(function ($customer) {
    //
});

For each of the created model instance, we then create one customer address record. We save this one-to-one relationship with the save() method:

$address = factory(App\CustomerAddress::class)->make();
$customer->address()->save($address);

We also create 5 purchase records for each customer. We then save this one-to-many relationship with saveMany() method:

$purchases = factory(App\CustomerPurchase::class, 5)->make();
$customer->purchases()->saveMany($purchases);

To run the database seeders, run the following artisan command on our terminal:

$ php artisan db:seed

# Or if you just want to run a particular seeder class
$ php artisan db:seed --class=CustomersTableSeeder

And if you want to re-run all of your migration files, you may pass the --seed option to run the seeders.

$ php artisan migrate:refresh --seed

Our customers, customer_addresses, and customer_purchases should now be filled with random data.

Risan Bagja