add foreign keys and extend models

device-app/app/Models/Device.php

@@ -2,8 +2,11 @@
 
 namespace App\Models;
 
-use Illuminate\Database\Eloquent\Factories\HasFactory;
+use App\Models\OwnerTransaction;
+use App\Models\LocationTransaction;
+use App\Models\PurchasingInformation;
 use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Factories\HasFactory;
 
 class Device extends Model
 {
@@ -24,4 +27,16 @@ class Device extends Model
 
     //Timestamps are disabled.
     public $timestamps = false;
+
+    public function owners() {
+        return $this->hasMany(OwnerTransaction::class, 'device_id');
+    }
+
+    public function locations() {
+        return $this->hasMany(LocationTransaction::class, 'device_id');
+    }
+
+    public function purchasing() {
+        return $this->belongsTo(PurchasingInformation::class, 'device_id');
+    }
 }