Introduction

This extended version of HasManyThrough allows relationships with unlimited intermediate models.
It supports many-to-many and polymorphic relationships and all their possible combinations. It also supports some third-party packages.

Supports Laravel 5.5.29+.

Installation

composer require staudenmeir/eloquent-has-many-deep:"^1.7"

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

composer require staudenmeir/eloquent-has-many-deep:"^^^^1.7"

Versions

Laravel	Package
5.5–5.7	1.7
5.8	1.8
6.x	1.11
7.x	1.12
8.x	1.14
9.x	1.17
10.x	1.18

Usage

The package offers two ways of defining deep relationships:
You can concatenate existing relationships or specify the intermediate models, foreign and local keys manually.

• Concatenating Existing Relationships
  • Constraints
  • Third-Party Packages
• Defining Relationships Manually
  • HasMany
  • ManyToMany
  • MorphMany
  • MorphToMany
  • MorphedByMany
  • BelongsTo
  • HasOneDeep
  • Composite Keys
• Intermediate and Pivot Data
• Intermediate and Pivot Constraints
• Table Aliases
• Soft Deleting
• Reversing Relationships

Concatenating Existing Relationships

Consider this example from the Laravel documentation with an additional level:
Country → has many → User → has many → Post → has many → Comment

You can define a HasManyDeep relationship by concatenating existing relationships:

class Country extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function comments()
    {
        return $this->hasManyDeepFromRelations($this->posts(), (new Post())->comments());
    }

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

class Post extends Model
{
    public function comments()
    {
        return $this->hasMany(Comment::class);
    }
}

Define a HasOneDeep relationship with hasOneDeepFromRelations() if you only want to retrieve a single related instance.

Constraints

By default, constraints from the concatenated relationships are not transferred to the new deep relationship. Use hasManyDeepFromRelationsWithConstraints() with the relationships as callable arrays to apply these constraints:

class Country extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function comments()
    {
        return $this->hasManyDeepFromRelationsWithConstraints([$this, 'posts'], [new Post(), 'comments']);
    }

    public function posts()
    {
        return $this->hasManyThrough(Post::class, User::class)->where('posts.published', true);
    }
}

class Post extends Model
{
    public function comments()
    {
        return $this->hasMany(Comment::class)->withTrashed();
    }
}

Make sure to qualify the constraints' column names if they appear in multiple tables:
->where('posts.published', true) instead of ->where('published', true)

Third-Party Packages

Besides native Laravel relationships, you can also concatenate relationships from these third-party packages:

• https://github.com/staudenmeir/eloquent-json-relations: BelongsToJson, HasManyJson, HasManyThroughJson
• https://github.com/staudenmeir/laravel-adjacency-list: Tree relationships
• https://github.com/topclaudy/compoships: BelongsTo, HasMany, HasOne

Defining Relationships Manually

If you don't have all the necessary existing relationships to concatenate them, you can also define a deep relationship manually by specifying the intermediate models, foreign and local keys.

HasMany

Consider this example from the Laravel documentation with an additional level:
Country → has many → User → has many → Post → has many → Comment

class Country extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function comments()
    {
        return $this->hasManyDeep(Comment::class, [User::class, Post::class]);
    }
}

Just like with hasManyThrough(), the first argument of hasManyDeep() is the related model. The second argument is an array of intermediate models, from the far parent (the model where the relationship is defined) to the related model.

By default, hasManyDeep() uses the Eloquent conventions for foreign and local keys. You can also specify custom foreign keys as the third argument and custom local keys as the fourth argument:

class Country extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function comments()
    {
        return $this->hasManyDeep(
            Comment::class,
            [User::class, Post::class], // Intermediate models, beginning at the far parent (Country).
            [
               'country_id', // Foreign key on the "users" table.
               'user_id',    // Foreign key on the "posts" table.
               'post_id'     // Foreign key on the "comments" table.
            ],
            [
              'id', // Local key on the "countries" table.
              'id', // Local key on the "users" table.
              'id'  // Local key on the "posts" table.
            ]
        );
    }
}

You can use null placeholders for default keys:

class Country extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function comments()
    {
        return $this->hasManyDeep(Comment::class, [User::class, Post::class], [null, 'custom_user_id']);
    }
}

ManyToMany

You can include ManyToMany relationships in the intermediate path.

ManyToMany → HasMany

Consider this example from the Laravel documentation with an additional HasMany level:
User → many to many → Role → has many → Permission

Add the pivot tables to the intermediate models:

class User extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function permissions()
    {
        return $this->hasManyDeep(Permission::class, ['role_user', Role::class]);
    }
}

If you specify custom keys, remember to swap the foreign and local key on the "right" side of the pivot table:

class User extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function permissions()
    {
        return $this->hasManyDeep(
            Permission::class,
            ['role_user', Role::class], // Intermediate models and tables, beginning at the far parent (User).
            [           
               'user_id', // Foreign key on the "role_user" table.
               'id',      // Foreign key on the "roles" table (local key).
               'role_id'  // Foreign key on the "permissions" table.
            ],
            [          
              'id',      // Local key on the "users" table.
              'role_id', // Local key on the "role_user" table (foreign key).
              'id'       // Local key on the "roles" table.
            ]
        );
    }
}

ManyToMany → ManyToMany

Consider this example from the Laravel documentation with an additional ManyToMany level:
User → many to many → Role → many to many → Permission

Add the pivot table to the intermediate models:

class User extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function permissions()
    {
        return $this->hasManyDeep(Permission::class, ['role_user', Role::class, 'permission_role']);
    }
}

MorphMany

You can include MorphMany relationships in the intermediate path.

Consider this example from the Laravel documentation with an additional level:
User → has many → Post → morph many → Comment

Specify the polymorphic foreign keys as an array, starting with the *_type column:

class User extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function postComments()
    {
        return $this->hasManyDeep(
            Comment::class,
            [Post::class],
            [null, ['commentable_type', 'commentable_id']]
        );
    }
}

MorphToMany

You can include MorphToMany relationships in the intermediate path.

Consider this example from the Laravel documentation with an additional level:
User → has many → Post → morph to many → Tag

Add the pivot table to the intermediate models and specify the polymorphic foreign keys as an array, starting with the *_type column:

class User extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function postTags()
    {
        return $this->hasManyDeep(
            Tag::class,
            [Post::class, 'taggables'],
            [null, ['taggable_type', 'taggable_id'], 'id'],
            [null, null, 'tag_id']
        );
    }
}

Remember to swap the foreign and local key on the "right" side of the pivot table:

MorphedByMany

You can include MorphedByMany relationships in the intermediate path.

Consider this example from the Laravel documentation with an additional level:
Tag → morphed by many → Post → has many → Comment

Add the pivot table to the intermediate models and specify the polymorphic local keys as an array, starting with the *_type column:

class Tag extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function postComments()
    {
        return $this->hasManyDeep(
            Comment::class,
            ['taggables', Post::class],
            [null, 'id'],
            [null, ['taggable_type', 'taggable_id']]
        );
    }
}

BelongsTo

You can include BelongsTo relationships in the intermediate path:
Tag → morphed by many → Post → belongs to → User

Swap the foreign and local key:

class Tag extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function postAuthors()
    {
        return $this->hasManyDeep(
            User::class,
            ['taggables', Post::class],
            [null, 'id', 'id'],
            [null, ['taggable_type', 'taggable_id'], 'user_id']
        );
    }
}

HasOneDeep

Define a HasOneDeep relationship if you only want to retrieve a single related instance:

class Country extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function latestComment()
    {
        return $this->hasOneDeep(Comment::class, [User::class, Post::class])
            ->latest('comments.created_at');
    }
}

Composite Keys

If multiple columns need to match between two tables, you can define a composite key with the CompositeKey class.

Consider this example from the compoships documentation with an additional level:
User → has many (matching team_id & category_id) → Task → belongs to → Project

use Staudenmeir\EloquentHasManyDeep\Eloquent\CompositeKey;

class User extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function projects()
    {
        return $this->hasManyDeep(
            Project::class,
            [Task::class],
            [new CompositeKey('team_id', 'category_id'), 'id'],
            [new CompositeKey('team_id', 'category_id'), 'project_id']
        );
    }
}

Intermediate and Pivot Data

Use withIntermediate() to retrieve attributes from intermediate tables:

public function comments()
{
    return $this->hasManyDeep(Comment::class, [User::class, Post::class])
        ->withIntermediate(Post::class);
}

foreach ($country->comments as $comment) {
    // $comment->post->title
}

By default, this will retrieve all the table's columns. Be aware that this executes a separate query to get the list of columns.

You can specify the selected columns as the second argument:

public function comments()
{
    return $this->hasManyDeep(Comment::class, [User::class, Post::class])
        ->withIntermediate(Post::class, ['id', 'title']);
}

As the third argument, you can specify a custom accessor:

public function comments()
{
    return $this->hasManyDeep(Comment::class, [User::class, Post::class])
        ->withIntermediate(Post::class, ['id', 'title'], 'accessor');
}

foreach ($country->comments as $comment) {
    // $comment->accessor->title
}

If you retrieve data from multiple tables, you can use nested accessors:

public function comments()
{
    return $this->hasManyDeep(Comment::class, [User::class, Post::class])
        ->withIntermediate(Post::class)
        ->withIntermediate(User::class, ['*'], 'post.user');
}

foreach ($country->comments as $comment) {
    // $comment->post->title
    // $comment->post->user->name
}

Use withPivot() for the pivot tables of BelongsToMany and MorphToMany/MorphedByMany relationships:

public function permissions()
{
    return $this->hasManyDeep(Permission::class, ['role_user', Role::class])
        ->withPivot('role_user', ['expires_at']);
}

foreach ($user->permissions as $permission) {
    // $permission->role_user->expires_at
}

You can specify a custom pivot model as the third argument and a custom accessor as the fourth:

public function permissions()
{
    return $this->hasManyDeep(Permission::class, ['role_user', Role::class])
        ->withPivot('role_user', ['expires_at'], RoleUser::class, 'pivot');
}

foreach ($user->permissions as $permission) {
    // $permission->pivot->expires_at
}

Intermediate and Pivot Constraints

You can apply constraints on intermediate and pivot tables:

class Country extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function comments()
    {
        return $this->hasManyDeep(Comment::class, [User::class, Post::class]);
    }
}

$commentsFromActiveUsers = $country->comments()->where('users.active', true)->get();

Table Aliases

If your relationship path contains the same model multiple times, you can specify a table alias:

class Post extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function commentReplies()
    {
        return $this->hasManyDeep(Comment::class, ['App\Comment as alias'], [null, 'parent_id']);
    }
}

Use the HasTableAlias trait in the models you are aliasing:

class Comment extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasTableAlias;
}

For pivot tables, this requires custom models:

class User extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function permissions()
    {
        return $this->hasManyDeep(Permission::class, ['App\RoleUser as alias', Role::class]);
    }
}

class RoleUser extends Pivot
{
    use \Staudenmeir\EloquentHasManyDeep\HasTableAlias;
}

Use setAlias() to specify a table alias when concatenating existing relationships (Laravel 6+):

class Post extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function commentReplies()
    {
        return $this->hasManyDeepFromRelations(
            $this->comments(),
            (new Comment())->setAlias('alias')->replies()
        );
    }

    public function comments()
    {
        return $this->hasMany(Comment::class);
    }
}

class Comment extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasTableAlias;

    public function replies()
    {
        return $this->hasMany(self::class, 'parent_id');
    }
}

Soft Deleting

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

class Country extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

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

class User extends Model
{
    use SoftDeletes;
}

Reversing Relationships

You can define a HasManyDeep/HasOneDeep relationship by reversing an existing deep relationship using hasManyDeepFromReverse()/hasOneDeepFromReverse():

class Country extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function comments()
    {
        return $this->hasManyDeep(Comment::class, [User::class, Post::class]);
    }
}

class Comment extends Model
{
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function country()
    {
        return $this->hasOneDeepFromReverse(
            (new Country())->comments()
        );
    }
}

Contributing

Please see CONTRIBUTING and CODE OF CONDUCT for details.