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Database relationships are a key component of web application development, allowing you to easily organise and retrieve data. Laravel, a powerful PHP framework, offers a range of relationship types via its Eloquent ORM.

The Eloquent Has One Through Relationship in Laravel is a type of relationship that allows you to define a one-to-one relationship between two models, where the second model is accessed through an intermediate model.

In this article, we will look at the Laravel 10 “Has One Through” relationship, which allows you to obtain related data from distant tables via intermediate connections.

For this tutorial we will consider a people table, brokers table and homes table. This means a person will contact a broker to take a home

Person -> Broker -> Home

Let’s get started.

Laravel Installation

Open terminal and run this command to create a laravel project.

composer create-project laravel/laravel myblog

It will create a project folder with name myblog inside your local system.

To start the development server of laravel –

php artisan serve

URL: http://127.0.0.1:8000

Assuming laravel already installed inside your system.

Create Database & Connect

To create a database, either we can create via Manual tool of PhpMyadmin or by means of a mysql command.

CREATE DATABASE laravel_app;

To connect database with application, Open .env file from application root. Search for DB_ and update your details.

DB_CONNECTION=mysql
DB_HOST=127.0.0.1
DB_PORT=3306
DB_DATABASE=laravel_app
DB_USERNAME=root
DB_PASSWORD=root

Create Migrations & Database Tables

To get idea about “has one through” relationship you need few migration files,

People migration for people table to store people data
Broker migration for brokers table to store brokers
Home Migration for homes table to store homes data

Open project into terminal and run these artisan commands,

php artisan make:migration create_people_table

php artisan make:migration create_brokers_table

php artisan make:migration create_homes_table

It will create two migration files xxx_create_people_table.php, xxx_create_brokers_table.php, and xxx_create_homes_table.php inside location /database/migrations.

Open xxx_create_people_table.php and write this complete code into it,

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('people', function (Blueprint $table) {
            $table->id();
            $table->string("name", 120);
            $table->string("email", 120)->unique();
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('people');
    }
};

Open xxx_create_brokers_table.php and write this code into it,

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('brokers', function (Blueprint $table) {
            $table->id();
            $table->string("name", 120);
            $table->string("email", 120)->unique();
            $table->foreignId('person_id')->constrained('people');
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('brokers');
    }
};

Open xxx_create_homes_table.php and write this complete code into it,

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('homes', function (Blueprint $table) {
            $table->id();
            $table->string("title", 155);
            $table->text("location");
            $table->foreignId('broker_id')->constrained('brokers');
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('homes');
    }
};

Run Migrations

Next, you need to migrate migrations.

php artisan migrate

This command will create tables inside database.

Setup Model with Has-One-Through Relationship

Back to terminal and run these artisan commands,

php artisan make:model Person

php artisan make:model Broker

php artisan make:model Home

These commands will create three files Person.php, Broker.php and Home.php inside /app/Models folder.

Open Person.php and write this complete code into it.

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Relations\HasOneThrough;
use Illuminate\Database\Eloquent\Model;
use App\Models\Home;
use App\Models\Broker;

class Person extends Model
{
    use HasFactory;

    public function homeInformation(): HasOneThrough
    {
        return $this->hasOneThrough(Home::class, Broker::class);
    }
}

$this->hasOneThrough(Home::class, Broker::class); This is establishing Has One Through Relationship.

The first argument passed to the hasOneThrough method is the name of the final model we wish to access, while the second argument is the name of the intermediate model.

Rest for all models like for Broker.php and Home.php code will be same as default code.

Usage

$home = Person::find($person_id)->homeInformation;

How To Use Relation in Laravel Controller?

Let’s test with a dummy application controller file.

Open any controller say DataController.php file from /app/Http/Controllers folder.

Here, you can see a method in which we used model method as a property.

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Models\Person;

class DataController extends Controller
{
    // To get home detail of a person
    public function getHome($person_id)
    {
        return Person::find($person_id)->homeInformation;
    }
}

Explanation,

Person::find($person_id)->homeInformation; It returns the home information by person_id through broker. And Broker is attached with a home detail. It is showing has one through relationship.

Add Route

Open web.php from /routes folder and add this route into it,

//...

use App\Http\Controllers\DataController;

Route::get('home-info/{id}', [DataController::class, 'getHome']);

//...

Application Testing

Run this command into project terminal to start development server,

php artisan serve

URL

Get Homes by person id – http://127.0.0.1:8000/home-info/1

That’s it.

We hope this article helped you to learn about Laravel 10 Eloquent Has One Through Relationship Tutorial in a very detailed way.

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