Possible to merge two Relations?

[NicksonYap]

Hi

I've successfully implemented this Laravel package, it's awesome

I have two possible Relations:

Order -> belongs to many -> DeliveryOrder -> belongs to many -> Invoices

Order -> belongs to many -> Invoices

Some Orders can relate directly to Invoices, some will have to go through DeliveryOrder

They have different possible paths but the start and end Models of the possible paths are the same

I'm able to use hasManyDeep to get both relations, separately

But how can we add support or workaround to combine the two Relations into one?

(not asking to convert into a Collection or array and merge them, that's cheating)

Thanks!

[staudenmeir]

Should the merged relationship be a "real" relationship (with support for eager loading etc.)? Or do you just want to get the invoices from both sources in a single query?

[NicksonYap]

@staudenmeir
Real relationship with eager loading 😅

[staudenmeir]

I don't see a (feasible) way to do this.

[NicksonYap]

If you look at it, it's not literally combining Relations

The Starting and Ending model must be the same

But the ones in between can jump to another model or skip a model

So I suppose there is like an OR when doing JOINS?

Not sure if i made sense :/

[staudenmeir]

I don't think it's that simple. The only way I see is a UNION query.

[NicksonYap]

@staudenmeir

I've managed to union() two manyToMany & hasManyDeep relations, however there were a number of workarounds required.

one would normally do this: (the following does not work)

public function combined_relations(){
  return $this->firstRelation()->union($this->secondRelation());
}

However because Laravel has issues applying union to manyToMany relationships, this has to be done:

public function combined_relations(){
  //fix due to extra columns from pivot tables
  return $this->firstRelation()->select('table_name.*')->union($this->secondRelation()->select('table_name.*'));
}

But it returns a Builder instance, not a Relations instance like belongsToMany() or hasMany()

So it does not work with whereHas() or with()

Do you know how to convert a Builder instance into a Relations instance?

I managed to get an array and hydrate() it back into Eloquent/Model

[staudenmeir]

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(
    'all_invoices', [(new Order)->invoices(), (new Order)->deliveryInvoices()]
);

If you want to get unique results:

use Staudenmeir\LaravelMergedRelations\Facades\Schema;

Schema::createMergeViewWithoutDuplicates(
    'all_invoices', [(new Order)->invoices(), (new Order)->deliveryInvoices()]
);

Then define the relationship:

class Order extends Model
{
    use \Staudenmeir\LaravelMergedRelations\Eloquent\HasMergedRelationships;

    public function allInvoices()
    {
        return $this->mergedRelationWithModel(Invoice::class, 'all_invoices');
    }

    public function invoices()
    {
        return $this->belongsToMany(Invoice::class);
    }

    public function deliveryInvoices()
    {
        return $this->hasManyDeep(
            Invoice::class,
            ['delivery_order_order', DeliveryOrder::class, 'delivery_order_invoice']
        );
    }
}

Order::find($id)->allInvoices;

Order::with('allInvoices')->get();

[androidhands]

@staudenmeir I have used your package and when run migration I get this error. Call to undefined method Staudenmeir\LaravelMergedRelations\Facades\Schema::createMergeView() . Please can you help me.

[staudenmeir]

@androidhands Please create a new issue:
https://github.com/staudenmeir/laravel-merged-relations/issues/new