pristavu / belongs-to-through

Laravel Eloquent BelongsToThrough relationships

Introduction

This inverse version of HasManyThrough allows BelongsToThrough relationships with unlimited intermediate models.

Supports Laravel 5.0+.

Installation

composer require staudenmeir/belongs-to-through:"^2.5"

Use this command if you are in PowerShell on Windows (e.g. in VS Code):

composer require staudenmeir/belongs-to-through:"^^^^2.5"

Usage

Consider this HasManyThrough relationship:
Country → has many → User → has many → Post

class Country extends Model
{
    public function posts()
    {
        return $this->hasManyThrough(Post::class, User::class);
    }
}

Use the BelongsToThrough trait in your model to define the inverse relationship:
Post → belongs to → User → belongs to → Country

class Post extends Model
{
    use \Znck\Eloquent\Traits\BelongsToThrough;

    public function country()
    {
        return $this->belongsToThrough(Country::class, User::class);
    }
}

You can also define deeper relationships:
Comment → belongs to → Post → belongs to → User → belongs to → Country

Supply an array of intermediate models as the second argument, from the related (Country) to the parent model (Comment):

class Comment extends Model
{
    use \Znck\Eloquent\Traits\BelongsToThrough;

    public function country()
    {
        return $this->belongsToThrough(Country::class, [User::class, Post::class]);
    }
}

You can specify custom foreign keys as the fifth argument:

class Comment extends Model
{
    use \Znck\Eloquent\Traits\BelongsToThrough;

    public function country()
    {
        return $this->belongsToThrough(
            Country::class,
            [User::class, Post::class], 
            null,
            '',
            [User::class => 'custom_user_id']
        );
    }
}

Table Aliases

If your relationship path contains the same model multiple times, you can specify a table alias (Laravel 6+):

class Comment extends Model
{
    use \Znck\Eloquent\Traits\BelongsToThrough;

    public function grandparent()
    {
        return $this->belongsToThrough(
            Comment::class,
            Comment::class . ' as alias', 
            null,
            '',
            [Comment::class => 'parent_id']
        );
    }
}

Use the HasTableAlias trait in the models you are aliasing:

class Comment extends Model
{
    use \Znck\Eloquent\Traits\HasTableAlias;
}

Soft Deleting

By default, soft-deleted intermediate models will be excluded from the result. Use withTrashed() to include them:

class Comment extends Model
{
    use \Znck\Eloquent\Traits\BelongsToThrough;

    public function country()
    {
        return $this->belongsToThrough(Country::class, [User::class, Post::class])
            ->withTrashed('users.deleted_at');
    }
}

class User extends Model
{
    use SoftDeletes;
}

Contributing

Please see CONTRIBUTING and CODE OF CONDUCT for details.

Credits

• Rahul Kadyan
• Danny Weeks
• All Contributors