CODEWITHSUNDEEP
phplaravelrelationshiphas-many-through
Edward
Edward

Reputation: 441

Laravel Polymorphic Relations Has Many Through

I have a Subscriber model

// Subscriber Model

id
user_id
subscribable_id
subscribable_type

public function user()
{
    return $this->belongsTo('App\User');
}

public function subscribable()
{
    return $this->morphTo();
}

And a Topic model

// Topic Model

public function subscribers()
{
    return $this->morphMany('App\Subscriber', 'subscribable');
}

And I want to get all users through Subscriber model, to notify them like

Notification::send($topic->users, new Notification($topic));

// Topic Model


public function users()
{
    return $this->hasManyThrough('App\User', 'App\Subscriber');
}

Any ideas?

Upvotes: 41

Views: 26342

Answers (4)

Matt Hanley
Matt Hanley

Reputation: 981

// Topic Model

public function users()
{
    return $this->hasManyThrough('App\User', 'App\Subscriber', 'subscribable_id')
        ->where(
            'subscribable_type', 
            array_search(static::class, Relation::morphMap()) ?: static::class
        );
}

Polymorphic hasManyThrough relationships are the same as any others, but with an added constraint on the subscribable_type, which can be retrieved from the Relation::morphMap() array, or by using the class name directly.

Upvotes: 88

mohamed al-ashry
mohamed al-ashry

Reputation: 261

try this package https://github.com/staudenmeir/eloquent-has-many-deep

then you could use it like this:

class Topic extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;
    public function users()
    {
        return $this->hasManyDeep(
            'App\User',
            ['App\Subscriber'],
            [null, ['subscribable_type', 'subscribable_id']]
        );
    }
}

Upvotes: 5

Maksim Ivanov
Maksim Ivanov

Reputation: 4311

What you're after is not hasManyThrough, but morphedByMany.

hasManyThrough is useful when you have A one-to-many B, B one-to-many C, and you want to use A to fetch many C.

What you have is a polymorphic pivot table sitting in the middle between A and C.

// Topic Model

public function users()
{
    return $this->morphedByMany('App\User', 'subscribable', 'pivot/subscriber_table_name');
}

Docs: https://laravel.com/docs/6.x/eloquent-relationships#many-to-many-polymorphic-relations

Upvotes: 12

Khalil Laleh
Khalil Laleh

Reputation: 1238

In addition to Matt's approach, the following code also could be another solution:

//Topic Model
public function users()
{
    return $this->belongsToMany(User::class, 'subscribers', 'subscribale_id', 'user_id')
        ->where('subscribale_type', static::class);
}

In this way Subscriber treated as a pivot table and second argument is table name for pivot.

The third argument is the foreign key name of the model on which you are defining the relationship, while the fourth argument is the foreign key name of the model that you are joining to. Read more here.

Consider the where clause after belongsToMany to filter only the current model.

Upvotes: 14

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