refactor: refactor receipt model

apps/fsm/migrations/0146_alter_registrationreceipt_form.py

@@ -0,0 +1,19 @@
+# Generated by Django 4.1.3 on 2024-07-28 23:01
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('fsm', '0145_remove_widget_be_corrected_problem_be_corrected'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='registrationreceipt',
+            name='form',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.PROTECT, related_name='registration_receipts', to='fsm.registrationform'),
+        ),
+    ]

apps/fsm/models.py

@@ -479,9 +479,7 @@ class CorrectionStatus(models.TextChoices):
         Other = "Other"
 
     created_at = models.DateTimeField(auto_now_add=True, blank=True, null=True)
-    # should be in every answer sheet child
-    form = models.ForeignKey('fsm.RegistrationForm', related_name='registration_receipts', null=True, blank=True,
-                             on_delete=models.SET_NULL)
+    form = models.ForeignKey('fsm.RegistrationForm', related_name='registration_receipts', on_delete=models.PROTECT)
     user = models.ForeignKey(
         'accounts.User', related_name='registration_receipts', on_delete=models.CASCADE)
     status = models.CharField(max_length=25, blank=False,