Question 245155 in Laravel Question posted in
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Laravel – hasManyThrough with a belongsToMany?

A Producer hasOne Distillery, a Distillery belongsToMany Whiskies.

A Whisky belongsToMany Distillery, a Distillery belongsTo Producer.

I wish to use hasManyThrough so, to get a Producer‘s Whiskies that belongToMany Distillery.

But how can I use hasManyThrough with belongsToMany relationship? I am aware you can specify the join keys, and I think you may be able to muck about with the pivot table, but I can’t figure it out.

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2

Answers


  1. 0

    I think that you relationships shoul look like this:

    // Producer model
public function distillery()
{
    return $this->hasOne(Distillery::class);
}

// Distillery model
public function producer()
{
    return $this->belongsTo(Producer::class);
}

public function whiskies()
{
    return $this->belongsToMany(Whisky::class);
}

// Whisky model
public function distilleries()
{
    return $this->belongsToMany(Distillery::class);
}

    To get the whiskies of a producer through a distillery, you can’t use hasManyThrough directly. Instead, you can define a custom method:

    // In the Producer model

public function whiskies()
{
    $distillery = $this->distillery;

    if($distillery) {
        return $distillery->whiskies;
    }

    return collect(); // empty collection if no distillery
}
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  2. 0

    Unfortunately, hasManyThrough does not directly support your scenario.

    However, you can achieve your goal by manually defining a custom method in your Producer model to retrieve the whiskies through distilleries.

    class Producer extends Model
{
    public function whiskies()
    {
        return Whisky::whereHas('distilleries', function ($query) {
            $query->where('producer_id', $this->id);
        });
    }
}

    Also define the inverse relationship in your Whisky model to get the producer

    class Whisky extends Model
{
    public function producer()
    {
        return $this->belongsTo(Producer::class, 'producer_id');
    }
}

    Now you can retrieve a producer’s whiskies like this:

    $producer = Producer::find($producerId);
$whiskies = $producer->whiskies;
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