laravel nova BelongsToMany - BelongsTo in pivot

Question

In Laravel Nova I have BelongsToMany Relationship (companies - pivot - requests).

In the Pivot table I have some additional columns which I access with the pivot fields (https://nova.laravel.com/docs/1.0/resources/relationships.html#belongstomany) which works great.

But now I have a special case where I have an additional BelongsTo relationship from the pivot table to a third table (states). I tried to define a BelongsTo Field in the pivot Fields, but that is not working.

BelongsToMany::make('Companies', 'companies', Company::class)->fields(new CompanyRequestFields()),

pivot fields:

class CompanyRequestFields
{
    /**
     * Get the pivot fields for the relationship.
     *
     * @return array
     */
    public function __invoke()
    {
        return [
            Number::make('preis'),
            Text::make('bezahlt'),
             BelongsTo::make('State', 'state', States::class),
        ];
    }
}

The error I get:

Call to undefined method Illuminate\Database\Eloquent\Relations\Pivot::state()

The relationship state() actually exists on the pivot Model and there is a Nova resource State class too.

So it looks like this is not supported from PivotFields? Or does anyone know if its possible to accomplish this?

Hi were you able to find any solution for this? – Aniket Feb 04 '20 at 17:45 — Aniket, Feb 04 '20 at 17:45

score 5 · Answer 1 · answered Dec 12 '18 at 09:23

I was not able to make it work with relationship in pivot table, but you can achieve it without a relationship definition like below.

class CompanyRequestFields
{
    public function __invoke()
    {
        $states= \App\State::all()->pluck('name', 'id');

        return [
            ...
            Select::make('State')->options($states),
        ];
    }
}

In \App\Request model

public function companies()
{
    return $this->belongsToMany('App\Company')->withPivot('state');
}

Hope this approach will help you.

score -5 · Answer 2 · answered Dec 11 '18 at 12:12

This is for Normal Laravel, Just change the sintaxis to laravel nova if you can!

In Normal Laravel, If you would like to define a custom model to represent the intermediate table of your relationship, you may call the using method when defining the relationship. Custom many-to-many pivot models should extend the Illuminate\Database\Eloquent\Relations\Pivot class while custom polymorphic many-to-many pivot models should extend the Illuminate\Database\Eloquent\Relations\MorphPivot class. In your case, you may define a custom Companies_requests pivot model:

<?php

namespace App;

use Illuminate\Database\Eloquent\Relations\Pivot;

class Companies_requests extends Pivot
{
    //
}

And reference it in your company model and request model:

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Company extends Model
{
    public function requests()
    {
        return $this->belongsToMany('App\Request')->using('App\Companies_requests');
    }
}

.

namespace App;

use Illuminate\Database\Eloquent\Model;

class Request extends Model
{
    public function companies()
    {
        return $this->belongsToMany('App\Company')->using('App\Companies_requests');
    }
}

Now, the ->pivot will be your new model!

Hope this is what you're searching for:)

laravel nova BelongsToMany - BelongsTo in pivot

2 Answers2