从父id获取兄弟姐妹并排除自己的Laravel关系

Question

CONTEXT

I am managing products. This is a shoe store. I would like to offer a view of the other variants.

The database is shaped like this:

For example you can have a leather shoe (id 1), and there is 3 variants of this shoe: a black (id 1), a brown (id 2), and a grey (id 3).

What I try to do is to construct a Laravel relationship to be able, from one variant, to get its siblings. Here is what it looks like in the database according to the example I mentioned.

SHOE
id
====
1

SHOE_VARIANT
id  shoeId  colorId
===================
1   1       1
2   1       2
3   1       3
...
8   2       5
9   3       2
10  3       4

In this case, if the user is viewing the black variant (id 1), I whish I could show him the 2 others variants (brown, id 2, and grey, id 3).

QUESTION

How can I construct a Laravel relationship in order to retrieve siblings from a parent id, and make sure the current record itself is not included?

EXPERIMENTS

I already tried to construct a relationship like below, but the current record itself is included and I can't figure out how to exclude the record itself because I did not find how to get the current id of the record.

// app/ShoeVariant.php

namespace App;

use Illuminate\Database\Eloquent\Model;

class ShoeVariant extends Model {
  public function siblings() {
    return $this->hasMany("App\ShoeVariant", "shoeId", "shoeId");
  }
}

This means:

For the current shoe variant, get the shoe variants that matches knowing that you should match the foreign column named "shoeId" and the local column named "shoeId"

So if 2 shoe variants share the same column "shoeId", this works. Stuck in excluding the current record from these results.

Answer 1

This should do what you want:

public function siblings() {
    return $this->hasMany('App\ShoeVariant', 'shoeId', 'shoeId')
                ->where('id', '!=', $this->id);
}

Just filter out the current variant by id and get all the others.

Alternatively, you can just make a new property:

public function getVariantsAttribute() {
    return $this->siblings->reject(function($elem) {
       return $elem->id == $this->id;
    });
}

And then use it in code like:

$variants = $model->variants; // all except this one