BelongsToThrough

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"

Versions

Laravel	Package
11.x	2.16
10.x	2.13
9.x	2.12
8.x	2.11
7.x	2.10
6.x	2.6
5.x	2.5

Usage

Custom Foreign Keys
Custom Local Keys
Table Aliases
Soft Deleting

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]);
    }
}

Custom Foreign Keys

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], 
            foreignKeyLookup: [User::class => 'custom_user_id']
        );
    }
}

Custom Local Keys

You can specify custom local keys for the relations:

VendorCustomerAddress → belongs to → VendorCustomer in VendorCustomerAddress.vendor_customer_id VendorCustomerAddress → belongs to → CustomerAddress in VendorCustomerAddress.address_id

You can access VendorCustomer from CustomerAddress by the following

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

    public function vendorCustomer(): BelongsToThrough
    {
        return $this->belongsToThrough(
            VendorCustomer::class,
            VendorCustomerAddress::class,
            foreignKeyLookup: [VendorCustomerAddress::class => 'id'],
            localKeyLookup: [VendorCustomerAddress::class => 'address_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',
            foreignKeyLookup: [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.

staudenmeir/belongs-to-through

Laravel Eloquent BelongsToThrough relationships