One to many polymorphic relationship - eloquent

Question

It's a common situation but I somehow couldn't manage to find a reasonable solution so far. Basically I need the following:
I have the model House which contains a couple of other models (e.g. Brick, 'Stick', 'Chair' etc.). Each one of them has a belongsTo relation to the House (so basically in the sticks, chairs and bricks table there is a house_id column). Each model contains a public function house() method which returns the house they're part of. Now comes the problem that I'd like to get all of a house's supplies by a method, let's say for example public function supplies(), which should return a collection of instances of the classes Stick, Chair and Brick. Is there any convenient way to achieve that? Could I for example unite those classes by a trait and somehow point to that trait in the house's method or maybe with a BaseClass, let's say Supply, that all the supplies should inherit? Any recommendances? Any help is greatly appreciated and thanks in advance!

Answer 1

There is no built-in support for this in Laravel.
You can define separate HasMany relationships and then merge them with an accessor:
class House extends Model {
public function bricks() {
return $this->hasMany(Brick::class);
}
public function chairs() {
return $this->hasMany(Chair::class);
}
public function sticks() {
return $this->hasMany(Stick::class);
}
public function getSuppliesAttribute() {
return $this->bricks->toBase()->merge($this->chairs)->merge($this->sticks);
}
}
$supplies = $house->supplies;
+++ UPDATE +++
I've created a package for merging relationships using views:
https://github.com/staudenmeir/laravel-merged-relations
First, create the merge view in a migration:
use Staudenmeir\LaravelMergedRelations\Facades\Schema;
Schema::createMergeView(
'supplies', [(new House)->bricks(), (new House)->chairs(), (new House)->sticks()]
);
Then define the relationship:
class House extends Model
{
use \Staudenmeir\LaravelMergedRelations\Eloquent\HasMergedRelationships;
public function supplies()
{
return $this->mergedRelation('supplies');
}
}
Use it like any other relationship:
House::find($id)->supplies;
House::find($id)->supplies()->paginate();
House::with('supplies')->get();