Eloquent belongsToMany and Three Tables (Including Pivot) - mysql

Question

I am working on an Ecommerce project using the Laravel framework. I have a products table, a flavors table, and a flavor_product table (I believe this is referred to as a pivot table). I have a Product model and a Flavor model (from what I have read it is unnecessary to create a model for the pivot table).
In the Product model I have defined the following relationship:
public function flavors()
{
return $this->belongsToMany('App\Flavor');
}
In the Flavor model I have defined the following relationship:
public function products()
{
return $this->belongsToMany('App\Product');
}
Now, in my Product controller I have attempted the following:
$flavors = Product::select('id')->with('flavors')->get();
which gets sent to the applicable view (product.blade.php).
In product.blade.php I have the following:
#foreach ($flavors as $flavor)
<select id="product-flavor" class="bs-select">
<option value="{{ $flavor }}">{{ $flavor }}</option>
</select>
#endforeach
So, what is the giving me? Well, it's showing me the following:
{"id":1,"flavors":[{"id":1,"name":"Cake Batter","created_at":"2018-05-29 20:12:56","updated_at":"2018-05-29 20:12:56","pivot":{"product_id":1,"flavor_id":1}},{"id":2,"name":"Caramel Coffee","created_at":"2018-05-29 20:48:25","updated_at":"2018-05-29 20:48:25","pivot":{"product_id":1,"flavor_id":2}},{"id":3,"name":"Chocolate Milkshake","created_at":"2018-05-29 20:49:09","updated_at":"2018-05-29 20:49:09","pivot":{"product_id":1,"flavor_id":3}},{"id":4,"name":"Cookies & Cream","created_at":"2018-05-29 20:49:50","updated_at":"2018-05-29 20:49:50","pivot":{"product_id":1,"flavor_id":4}},{"id":5,"name":"Vanilla Milkshake","created_at":"2018-05-29 20:50:16","updated_at":"2018-05-29 20:50:16","pivot":{"product_id":1,"flavor_id":5}}]}
which I definitely don't want all of that. All I want is to retrieve the name of the flavors associated to that product via the pivot table.
How can I proceed on this?
Edit
The following code is in the ShopController.php (regarding how the product is retrieved and displayed):
/**
* Display the specified resource.
*
* #param string $slug
* #return \Illuminate\Http\Response
*/
public function show($slug)
{
$product = Product::where('slug', $slug)->firstOrFail();
$mightAlsoLike = Product::where('slug', '!=', $slug)->mightAlsoLike()->get();
return view('product')->with([
'product' => $product,
'mightAlsoLike' => $mightAlsoLike,
]);
}
From web.php:
Route::get('/shop/{product}', 'ShopController#show')->name('shop.show');

Answer 1

What you're doing here is telling Laravel to select id from all products and retrieve all of their associated flavours.
Product::select('id') // <-- Will only select `id` attribute from the `products` table
->with('flavors') // <-- Will attach associated flavors to the product id
->get(); // <-- End the query (get all product ids and their flavours)
In your case, you don't want to select all the products and you have the relation set up correctly. So what you should do is call ->with('flavors') on your original query (actually not needed in this case, since you won't run into n+1 problems but still good practice):
$product = Product::where('slug', $slug)->with('flavors')->firstOrFail();
$mightAlsoLike = Product::where('slug', '!=', $slug)->mightAlsoLike()->get();
return view('product')->with([
'product' => $product,
'mightAlsoLike' => $mightAlsoLike,
]);
And then just call the $product->flavors in the view:
#foreach ($product->flavors as $flavor)
<select id="product-flavor" class="bs-select">
<option value="{{ $flavor }}">{{ $flavor }}</option>
</select>
#endforeach
The above view code would work as-is without actually calling ->with('flavors') on the query. ->with(...) eager loads the relationship and is good practice to explicitly call when loading multiple parents, to avoid n+1 problem (performance!).
But in your case you're only showing the flavors from 1 product, so there's no real advantage to calling it explicitly (except clearer code).
Edit to address the comment:
<select id="product-flavor" class="bs-select">
#foreach ($product->flavors as $flavor)
<option value="{{ $flavor->id }}">{{ $flavor->name }}</option>
#endforeach
</select>
You're seeing multiple selects because you're printing the whole select inside the loop instead of just printing the options.
And to display any attribute from the current flavor, just call the attribute name: $flavor->name for example.