my changes

app/File.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace App;
+
+use Illuminate\Database\Eloquent\Model;
+
+class File extends Model
+{
+    protected $table = 'document_files';
+    public $timestamps = false;
+    
+
+    protected $fillable = [];
+    
+    public function dataset()
+    {
+        return $this->belongsTo(\App\Dataset::class, 'document_id', 'id');
+    }
+}