CODEWITHSUNDEEP
laravellaravel-5
Dev
Dev

Reputation: 1073

When to use belongsTo and when hasMany?

If I am not right, please correct me.

There is table products and categories.

Each product has own category. So, it can be more that one.

So, no I need to select all products by specified category.

What kind of relation I should use in model: belongsTo, or hasMany? Is it important sequence?

Upvotes: 0

Views: 161

Answers (1)

Sam
Sam

Reputation: 20486

Since products have multiple categories and categories can have multiple products, this is known as a many-to-many SQL relationship.

If we go to the Laravel Eloquent documentation, you'll see that you want to use belongsToMany(). This means, if you want to be able to retrieve all of your products from a category, you would do something like this (shamelessly copied from Laravel's documentation):

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Category extends Model
{
    /**
     * The products that belong to the category.
     */
    public function products()
    {
        return $this->belongsToMany('App\Product');
    }
}

And, of course the other side of this many-to-many relationship is very similar:

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Product extends Model
{
    /**
     * The categories that belong to the product.
     */
    public function categories()
    {
        return $this->belongsToMany('App\Category');
    }
}

Now...if you want to fetch all products and subsequently find all categories for each product, you would do something like this:

$products = Product::all();
foreach($products as $product) {
    // var_dump($product);

    $categories = $product->categories();
    foreach($categories as $category) {
        // var_dump($category);
    }
}

Upvotes: 2

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