Laravel 8- Eloquent Relationships Tutorial - One to One Relationship

This is Part 1 of our Laravel 8 - Eloquent Relationships Tutorial

Setup:
Let's create the laravel app erd-app

composer create-project laravel/laravel erd-app
cd erd-app

open .env and connect to your local database
php artisan serve

Then create students and profiles databases
php artisan make:migration create_students_table

go to app/database/migrations:

Schema::create('students', function (Blueprint $table) {
            $table->id();
            $table->string('first_name');
            $table->string('last_name');
            $table->timestamps();
        });

copy and save

php artisan make:migration create_profiles_table

go to app/database/migrations:

Schema::create('profiles', function (Blueprint $table) {
            $table->id();
            $table->foreignId('student_id');
            $table->string('email');
            $table->string('phone');
            $table->timestamps();
        });

copy and save

run migration to create tables
php artisan migrate
check in your database if successful

Now let's create the models student and profile
php artisan make:model Student
php artisan make:model Profile

models should be singular while the table is plural

One to One Relationships

Go to app/Models and open the two newly created models

define the one to one relationship
in Models/Student.php

protected $fillable = [
        'first_name',
        'last_name',
    ];

    public function profile()
    {
        return $this->hasOne('App\Models\Profile');
    }

in Models/Profile.php

  protected $fillable = [
        'student_id',
        'email',
        'phone',
    ];

    public function student()
    {
        return $this->belongsTo('App\Models\Student');
    }

this will define the relationship between the two models

Create the Controllers and Routes

php artisan make:controller StudentController

go to app/Http/Controllers/StudentController

use App\Models\Student;

...

public function index(){
        $stu = Student::find(1);
        dd($stu);
    }

    public function store(){
        $student = new Student;
        $student->first_name = 'Dale';
        $student->last_name = 'Lanto';
        $student->save();
        dd($student);
    }

create routes in app/routes/web.php

Route::get('/students', [StudentController::class,'index'])->name('students');
Route::get('/students/store', [StudentController::class,'store'])->name('store');

in your browser go to http://localhost:8000/students/store to create 1 entry in the database

go to http://localhost:8000/students to check the models

it should look similar to:

Now lets create 1 entry for the profile

create new route

Route::get('/students/store/profile', [StudentController::class,'store_profile'])->name('storeProfile');

create new function in controller

public function store_profile(){

        $student = Student::find(1);

        $profile = new Profile;
        $profile->student_id = $student->id;
        $profile->email = '[e-mail]';
        $profile->phone = '7623423814';
        $profile->save();

        dd($profile);
    }

go to http://localhost:8000/students/store/profile to create 1 entry in the database

update the index function by calling profile from student

public function index(){
        $student = Student::find(1);
        dd($student->profile);
    }

go to http://localhost:8000/students to check

it should look similar to:

Hurray! We have successfully created our One to One Relationship.

For best practices it is best to include the foreign_key and local_key/owner_key in the model.

Let's go to Models/Profile.php and change the code to this

public function student()
    {
        // return $this->belongsTo('Model', 'foreign_key', 'owner_key'); 
        return $this->belongsTo('App\Models\Student','student_id','id');
    }

Now let's access the profile from the student model

public function index(){
        $student = Student::with('profile')->get();
        dd($student);
    }

Result:

Click this link to proceed with the next tutorial - One to Many Relationship!