Laravel 8 Eloquent one-to-many relationship data retrieval issue - eloquent

Question

I have been following a tutorial on the Internet about the one-to-many relationships in Eloquent (in Laravel 8). It has a simple mySQL database with two simple tables ("cars" and "car_models") that were created by using Laravel migration.
Here is the migration file:
<?php
use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;
class CreateCarsTable extends Migration
{
/**
* Run the migrations.
*
* #return void
*/
public function up()
{
Schema::create('cars', function (Blueprint $table) {
$table->increments('id');
$table->string('name');
$table->integer('founded');
$table->longText('description');
$table->timestamps();
});
Schema::create('car_models', function (Blueprint $table) {
$table->increments('id');
$table->unsignedInteger('car_id');
$table->string('model_name');
$table->timestamps();
$table->foreign('car_id')
->references('id')
->on('cars')
->onDelete('cascade');
});
}
/**
* Reverse the migrations.
*
* #return void
*/
public function down()
{
Schema::dropIfExists('cars');
}
}
Here is the "cars" table:
mysql> desc cars;
+-------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------+--------------+------+-----+---------+----------------+
| id | int unsigned | NO | PRI | NULL | auto_increment |
| name | varchar(255) | NO | | NULL | |
| founded | int | NO | | NULL | |
| description | longtext | NO | | NULL | |
| created_at | timestamp | YES | | NULL | |
| updated_at | timestamp | YES | | NULL | |
+-------------+--------------+------+-----+---------+----------------+
6 rows in set (0.34 sec)
mysql> select * from cars;
+----+------+---------+-------------------------------------+------------+------------+
| id | name | founded | description | created_at | updated_at |
+----+------+---------+-------------------------------------+------------+------------+
| 2 | Audi | 1908 | this is not the description of Audi | NULL | NULL |
+----+------+---------+-------------------------------------+------------+------------+
1 row in set (0.01 sec)
Here is the "car_models" table:
mysql> desc car_models;
+------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+----------------+
| id | int unsigned | NO | PRI | NULL | auto_increment |
| car_id | int unsigned | NO | MUL | NULL | |
| model_name | varchar(255) | NO | | NULL | |
| created_at | timestamp | YES | | NULL | |
| updated_at | timestamp | YES | | NULL | |
+------------+--------------+------+-----+---------+----------------+
5 rows in set (0.00 sec)
mysql> select * from car_models;
+----+--------+------------+------------+------------+
| id | car_id | model_name | created_at | updated_at |
+----+--------+------------+------------+------------+
| 5 | 2 | A1 | NULL | NULL |
| 6 | 2 | A3 | NULL | NULL |
| 7 | 2 | A5 | NULL | NULL |
+----+--------+------------+------------+------------+
3 rows in set (0.00 sec)
What the sample project does is, all the rows from the "cars" table are pulled and feeds to a view. The user can then click on any of the brand names and the project will display all the models of that brand on another view. There are two models in the project that describe the data.
Here is the "Car" model:
<?php
namespace App\Models;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
class Car extends Model
{
use HasFactory;
protected $table = 'cars';
protected $primaryKey = 'id';
// public $timestamps = true;
protected $fillable = ['name', 'founded', 'description'];
public function carModels() {
return $this -> hasMany(CarModel::class, 'id', 'car_id');
}
}
Here is the "CarModel" model:
<?php
namespace App\Models;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
class CarModel extends Model
{
use HasFactory;
protected $table = 'cars';
protected $primaryKey = 'id';
public function car() {
return $this -> belongsTo(Car::class);
}
}
When I followed the tutorial strictly in the beginning, the project would bork with a 1054 error.
SQLSTATE[42S22]: Column not found: 1054 Unknown column 'cars.car_id' in 'where clause'
That was fixed after I added in the two optional parameters "foreign key" and "local key" to the hasMany() in the "Car" model. However, the resulting webpage says "No models found" when it should display "A1 A3 A5"
screenshot of output
Here is the relevant view:
#extends('layouts.app')
#section('contents')
<div class="m-auto w-4/5 py-24">
<div class="text-center">
<h1 class="text-5xl uppercase bold">{{ $car -> name }}</h1>
</div>
<div class="w-5/6 py-10">
<div class="m-auto">
<span class="uppercase text-blue-500 fold-bold text-xs italic">Founded: {{ $car -> founded }}</span>
<h2 class="text-gray-700 text-5xl hover:text-gray-500">
{{ $car -> name }}
</h2>
<p class="text-lg text-gray-700 py-6">{{ $car -> description }}</p>
</div>
<ul>
<p class="text-lg text-gray-700 py-3">Models:</p>
#forelse ($car -> carModels as $model)
<li class="inline italic text-gray-600 px-1 py-6">
{{ $model['model_name'] }}
</li>
#empty
<p>No models found</p>
#endforelse
</ul>
<hr class="mt-4 mb-8" />
</div>
</div>
#endsection
The id is correct as dd() returned a 2.
I have been staring at this for a few hours and my brains are now frizzled. A fresh pair of eyes can assist greatly. Thank you very much.

Answer 1

Okay, I found out what's wrong.
In the "CarModels" model, the protected $table should be "car_models," not "cars."