Proper way to set relations for a model that is made of two types of models

To implement the relationships for your meal planner, you can use a polymorphic many-to-many relationship. This allows a Meal to have multiple Ingredients and Dishes, and vice versa. Here's how you can set it up:

Database Migrations

You already have the meals and meal_components tables set up. You'll also need tables for ingredients and dishes.

// database/migrations/create_ingredients_table.php
Schema::create('ingredients', function (Blueprint $table) {
    $table->id();
    $table->string('name');
    $table->timestamps();
});

// database/migrations/create_dishes_table.php
Schema::create('dishes', function (Blueprint $table) {
    $table->id();
    $table->string('name');
    $table->timestamps();
});

Models

Define the relationships in your models using the morphToMany and morphedByMany methods.

// app/Models/Meal.php
namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Meal extends Model
{
    public function components()
    {
        return $this->morphToMany(MealComponent::class, 'mealable', 'meal_components');
    }
}

// app/Models/Ingredient.php
namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Ingredient extends Model
{
    public function meals()
    {
        return $this->morphedByMany(Meal::class, 'mealable', 'meal_components');
    }
}

// app/Models/Dish.php
namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Dish extends Model
{
    public function meals()
    {
        return $this->morphedByMany(Meal::class, 'mealable', 'meal_components');
    }
}

// app/Models/MealComponent.php
namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class MealComponent extends Model
{
    public function mealable()
    {
        return $this->morphTo();
    }
}

Usage

To associate an Ingredient or Dish with a Meal, you can use the attach method:

$meal = Meal::find(1);
$ingredient = Ingredient::find(1);
$dish = Dish::find(1);

// Attach an ingredient
$meal->components()->attach($ingredient, ['quantity' => 2]);

// Attach a dish
$meal->components()->attach($dish, ['quantity' => 1]);

Explanation

• Polymorphic Many-to-Many: This setup allows a Meal to have multiple Ingredients and Dishes through a single meal_components table.
• Morphs and MorphedByMany: These methods are used to define the polymorphic relationship. morphToMany is used in the Meal model to define the relationship with MealComponent, while morphedByMany is used in Ingredient and Dish models to define the inverse relationship.

This setup should give you the flexibility to manage meals composed of both ingredients and dishes efficiently.