fix cascade on shop product with user

shop/migrations/0026_alter_order_user.py

@@ -0,0 +1,21 @@
+# Generated by Django 5.1 on 2025-05-01 05:59
+
+import django.db.models.deletion
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('shop', '0025_alter_product_cut'),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='order',
+            name='user',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, to=settings.AUTH_USER_MODEL),
+        ),
+    ]

shop/models.py

@@ -111,7 +111,7 @@ class Coupon(models.Model):
         return self.discount_amount
 
 class Order(models.Model):
-    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, null=True, blank=True)
+    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.SET_NULL, null=True, blank=True)
     date_ordered = models.DateTimeField(auto_now_add=True)
     status = models.CharField(max_length=20, choices=OrderStatus.choices, default=OrderStatus.PENDING)
     total_price = models.DecimalField(max_digits=10, decimal_places=2, default=0.00)