Accessing Pivot table “3rd Model relationship” in Laravel Eloquent

问题

I have this Many-to-Many relation Laravel Eloquent relationship The Models are:

class Email extends Model //actually represent the email account
{
    protected $table = 'emails';

    protected $fillable = [
        'user_id',
        'name',
    ];

    public function messages() {
       return $this->belongsToMany(Message::class)->withPivot('email_subtype_id');
    }
}

class Message extends Model //actually represent the email message
{
    protected $table = 'messages';

    protected $fillable = [
        'subject',
        'body ',
    ];

    public function emails() {
        return $this->belongsToMany(Email::class)->withPivot('email_subtype_id');
    }
}

class EmailMessage extends Pivot //actually represent the pivot table
{
    protected $table = 'email_message';

    protected $fillable = [
        'email_id',
        'message_id',
        'email_subtype_id',
    ];

    public function email() {
        return $this->belongsTo(Email::class);
    }

    public function message() {
        return $this->belongsTo(Message::class);
    }

    //this is the relation to a third model called EmailSubtype
    //I want to include this relation to the Pivot when using it
    public function subtype() {
        return $this->belongsTo(EmailSubtype::class, 'email_subtype_id');
    }
}

class EmailSubtype extends Model //3rd Model need to be included with Pivot
{
    protected $table = 'email_subtypes';

    protected $fillable = [
        'name'
    ];

    public function pivotEmailSubtype(){
        return $this->hasMany(Pivot::class, 'email_subtype_id');
    }
}

I am able to do this in the Controller:

    $email = Email::find(1);

    foreach($email->messages as $message) {
        $subtype_id = $message->pivot->email_subtype_id;
        dd($subtype_id); //1 that relates to subtype: CC Email Account
        //also I can get the name indirectly away from the relation as follows:
        $subtypeName = EmailSubtype::find($subtype_id)->first()->name;
        dd($subtypeName);
    }

Here I am getting the email_subtype_id only by direct pivot relation but have to do extra work to get the related email sub-type name.

I need to get the email sub-type name [Directly] from the 3rd Model EmailSubtype relationship oneToMany [hasMany and belongsTo] that relates to Pivot model with EmailSubtype model using something like:

$message->pivot->subtypeName;

Any help please!

回答1:

Use this:

public function messages() {
   return $this->belongsToMany(Message::class)->withPivot('email_subtype_id') 
       ->using(EmailMessage::class);
}

$message->pivot->subtype->name

来源：https://stackoverflow.com/questions/50661239/accessing-pivot-table-3rd-model-relationship-in-laravel-eloquent

标签

php

laravel

eloquent

pivot