Laravel : Eloquent Relationships not work. Cannot show relationships in view - php

Question

I cannot show relationships in view after I set Eloquent Relationships in Model already.
In Model: Art_obj
class Art_obj extends Model
{
protected $table = 'art_objs';
protected $fillable = ['Id_no','Artist','Year','Title','Description','Origin','Epoch','Picture','Type_of_art'];
public function Painting(){
return $this->hasOne(Painting::class,'Id_no');
}
}
In Model: Painting
class Painting extends Model
{
protected $table = 'paintings';
protected $fillable = ['art_obj_Id_no','Paint_type','Drawn_on','Style'];
public function Art_obj(){
return $this->belongsTo(Art_obj::class,'Id_no');
}
}
In PaintingController
public function index()
{
$paintings = Painting::with('Art_obj');
return view('ArtObj.Painting', compact('paintings'));
}
in Painting.blade.php
<table class="table table-bordered table-striped">
<tr>
<th>Title</th>
<th>Paint type</th>
<th>Drawn on</th>
<th>Style</th>
</tr>
#foreach($paintings as $row)
<tr>
<td>{{$row->Art_obj->Title}}</td>
<td>{{$row['Paint_type']}}</td>
<td>{{$row['Drawn_on']}}</td>
<td>{{$row['Style']}}</td>
</tr>
#endforeach
</table>
It does not have any field show in view.
enter image description here

Answer 1

If you aren't using id as your model's primary key, you need to set the primary key property in your models:
protected $primaryKey = 'Id_no';
Eloquent will also assume that each table has a primary key column named id. You may define a protected $primaryKey property to override this convention.
In addition, Eloquent assumes that the primary key is an incrementing integer value, which means that by default the primary key will be cast to an int automatically. If you wish to use a non-incrementing or a non-numeric primary key you must set the public $incrementing property on your model to false. If your primary key is not an integer, you should set the protected $keyType property on your model to string.
In addition, the relation must set the correct foreign and owner keys:
public function Art_obj(){
return $this->belongsTo(Art_obj::class,'Id_no', 'art_obj_Id_no');
}
and then retrieve the data:
$paintings = Painting::with('Art_obj')->get();
You should also check if the relation exists before attempting to access it:
#foreach($paintings as $row)
<tr>
#if (!is_null($row->Art_obj))
<td>{{$row->Art_obj->Title}}</td>
#else
<td>No Title</td>
#endif
<td>{{$row->Paint_type}}</td>
<td>{{$row->Drawn_on}}</td>
<td>{{$row->Style}}</td>
</tr>
#endforeach

Answer 2

You have not fetched data yet. Change your query to:
$paintings = Painting::with('Art_obj')->get();