Laravel 双多态关系

Question

I have the three tables articles , locations and companies . One row of each table can be linked with another row form one of the other tables over a fourth table calles links , where links looks like:

• id
• from_id
• from_type
• to_id
• to_type

For example, the article with the ID 1 could have a connection to the locations ID 1:

• id: 1
• from_id: 1
• from_type: App\Models\Article
• to_id: 1
• to_type: App\Models\Location

and the a connection with the company 3:

• id: 2
• from_id: 1
• from_type: App\Models\Article
• to_id: 3
• to_type: App\Models\Company

Which laravel relations would I need here? Its some kind of polymorphic many to many relation?

Answer 1

Actually this works with the links table

class Article extends Model
{
    use HasFactory;

    public function companies()
    {
        return $this->morphToMany(Company::class, 'to', 'links', 'from_id', 'to_id', 'id', 'id', 'to');
    }

    public function locations()
    {
        return $this->morphToMany(Location::class, 'to', 'links', 'from_id', 'to_id', 'id', 'id', 'to');
    }
}

Following test data in links table

This query

Article::with(['companies', 'locations'])->first();

//output
App\Models\Article {#2010
     id: 1,
     title: "Et molestiae consequuntur harum provident officia neque.",
     created_at: "2020-12-07 20:18:42",
     updated_at: "2020-12-07 20:18:42",
     companies: Illuminate\Database\Eloquent\Collection {#2003
       all: [
         App\Models\Company {#2007
           id: 3,
           name: "Ledner-Schumm",
           created_at: "2020-12-07 20:18:42",
           updated_at: "2020-12-07 20:18:42",
           pivot: Illuminate\Database\Eloquent\Relations\MorphPivot {#2004
             from_id: 1,
             to_id: 3,
             to_type: "App\Models\Company",
           },
         },
       ],
     },
     locations: Illuminate\Database\Eloquent\Collection {#1999
       all: [
         App\Models\Location {#1997
           id: 2,
           name: "Maiamouth",
           created_at: "2020-12-07 20:19:08",
           updated_at: "2020-12-07 20:19:08",
           pivot: Illuminate\Database\Eloquent\Relations\MorphPivot {#2001
             from_id: 1,
             to_id: 2,
             to_type: "App\Models\Location",
           },
         },
       ],
     },
   }

And for the inverse relation

class Company extends Model
{
    use HasFactory;

    public function articles()
    {
        return $this->morphedByMany(Article::class, 'from', 'links', 'to_id', 'from_id', 'id', 'id');
    }
}

Query

Company::with('articles')->find(3);

//Output
App\Models\Company {#2025
     id: 3,
     name: "Ledner-Schumm",
     created_at: "2020-12-07 20:18:42",
     updated_at: "2020-12-07 20:18:42",
     articles: Illuminate\Database\Eloquent\Collection {#2026
       all: [
         App\Models\Article {#2024
           id: 1,
           title: "Et molestiae consequuntur harum provident officia neque.",
           created_at: "2020-12-07 20:18:42",
           updated_at: "2020-12-07 20:18:42",
           pivot: Illuminate\Database\Eloquent\Relations\MorphPivot {#2049
             to_id: 3,
             from_id: 1,
             from_type: "App\Models\Article",
           },
         },
       ],
     },
   }