php - 拉维尔 : Cannot show many to many relationships in view

Question

我无法在 View 中显示多对多关系这是艺术品和展览的关系。我在许多展览 table 上有许多艺术品。但是当我打电话时它没有显示在视野中。

在模型中:

展览模型:

class Exhibition extends Model
{
    protected $table = 'exhibitions';
    protected $fillable = ['Ex_id','Name','Start_date','End_date','Limit_visit','picture'];
    protected $primaryKey = 'Ex_id';

    public function ExhibitionHasUser(){
        return $this->belongsTo(ExhibitionHasUser::class,'Ex_id', 'exhibition_id');
    }
}

展览有艺术模型

class ExhibitionHasArt extends Model
{
    protected $table = 'exhibition_has_art_objs';
    protected $fillable = ['list_no','exhibition_id','art_obj_Id_no'];
    protected $primaryKey = 'list_no';

    public function Exhibition(){
        return $this->hasMany(Exhibition::class,'exhibition_id');
    }

    public function Art_obj(){
        return $this->hasMany(Art_obj::class,'Id_no');
    }
}

Art_obj 模型

class Art_obj extends Model
{
    protected $table = 'art_objs';
    protected $fillable = ['Id_no','Type_of_art','Type_of_coll','Picture'];
    protected $primaryKey = 'Id_no';


    public function ExhibitionHasArt(){
        return $this->belongsTo(ExhibitionHasArt::class,'Id_no', 'art_obj_Id_no');
    }


}

在展览 Controller 中

 public function show($Ex_id)
    {
        $exhibitions = Exhibition::find($Ex_id);
        $exhibitionHasArts = ExhibitionHasArt::with('Art_obj')->get();
        return view('Exhibition.ShowExhibition', compact('exhibitions','exhibitionHasArts')); 
    }

在 View 中:我想展示从主键找到的展览并展示在这个展览中展示的艺术品。

<h1>Exhibition: {{$exhibitions->Ex_id}}</h1>
            <h2>Art objects in this exhibition</h2>
            <br>
            <table class="table table-bordered table-striped"> 
                <tr>
                    <td>exhibition_id</td>
                    <td>art_obj_Id_no</td>
                    <td>Title</td>
                </tr>
                @foreach($exhibitionHasArts as $row) 
                @if($row->exhibition_id == $exhibitions->Ex_id)
                    <tr>
                        <td>{{$row->exhibition_id}}</td>
                        <td>{{$row->art_obj_Id_no}}</td>
                        <td>{{$row->Art_obj->Title}}</td>
                    </tr>
                @endif
                @endforeach 
            </table> 

但它不起作用。

在表exhibition_has_art_objs

Answer 1

如果你真的想从数据透视表中获取数据，你应该像那样改变你的关系

please let me know if i am wrong.

展览模型:

class Exhibition extends Model
{
    protected $table = 'exhibitions';
    protected $fillable = ['Ex_id','Name','Start_date','End_date','Limit_visit','picture'];
    protected $primaryKey = 'Ex_id';

    public function ExhibitionHasUser(){
        return $this->hasMany(ExhibitionHasUser::class,'exhibition_id','Ex_id');
    }
}

展览有艺术模型

class ExhibitionHasArt extends Model
{
    protected $table = 'exhibition_has_art_objs';
    protected $fillable = ['list_no','exhibition_id','art_obj_Id_no'];
    protected $primaryKey = 'list_no';

    public function Exhibition(){
        return $this->belongsTo(Exhibition::class,'exhibition_id', 'Ex_id');
    }

    public function Art_obj(){
        return $this->belongsTo(Art_obj::class,'art_obj_Id_no', 'Id_no');
    }
}

Art_obj 模型

class Art_obj extends Model
{
    protected $table = 'art_objs';
    protected $fillable = ['Id_no','Type_of_art','Type_of_coll','Picture'];
    protected $primaryKey = 'Id_no';


    public function ExhibitionHasArt(){
        return $this->hasMany(ExhibitionHasArt::class,'art_obj_Id_no','Id_no');
    }
}