Laravel Lighthouse retrieving pivot data

Question

I'm using Laravel Lighthouse v4.16 to write the API for my project. Most of the mutations and queries work fine. But when I try to query for pivot data the results indicate that all pivot data is null.

So we have 3 different models I'll only show the relationship causing problems

User

public function companies(): BelongsToMany {
    return $this->belongsToMany(Company::class)
        ->using(CompanyUser::class)
        ->withPivot(
            'personnel_number',
        );
}

Company

public function users(): BelongsToMany {
   return $this->belongsToMany(User::class)->withPivot(
      'personnel_number',
   )->using(CompanyUser::class);
}

CompanyUser - extends pivot

public function user(): BelongsTo {
    return $this->belongsTo('App\Models\Tenant\User', 'user_id');
}

public function company(): BelongsTo {
    return $this->belongsTo('App\Models\Tenant\Company', 'company_id');
}

These are represented as the following types in Graphql

type User {
    id: ID!
    title: String
    companies: [Company!] @belongsToMany
    pivot: CompanyUser
}

type Company {
    id: ID!
    name: String
    users: [User] @belongsToMany
}

type CompanyUser {
    id: ID!
    personnel_number: String
    user: User! @belongsTo
    company: Company! @belongsTo
}

But when I run the following query the relationship is retrieved successfully but the pivot remains null.

{
 user(id: 1) {
    id
    first_name
    companies {
      id
      name
    }
    pivot {
      personnel_number
    }
  }
}

The result of that query looks like the one below

{
  "data": {
    "user": {
      "id": "1",
      "first_name": "Mike",
      "companies": [
        {
          "id": "1",
          "name": "company_name_1"
        }
      ],
      "pivot": null
     }
   }
}

Answer 1

The problem is the location of the pivot in your query, the pivot should be inside a relation ( ie: it is gonna be loaded after the join of the table is made to load the relation ).

So in order to achieve that, you need to make those changes:

• in the type:

type Company {
    id: ID!
    name: String

    users: [User] @belongsToMany
    pivot: CompanyUser # add
}

• in the query:

{
  user(id: 1) {
    id
    first_name
    companies {
      id
      name
      pivot { # moved here, inside companies relations
        personnel_number
      }
    }
  }
}

A remarque : you could manipulate the pivot data without having the CompanyUser class.