Add sorting, enforce foreign keys

ram/roster/migrations/0007_alter_rollingclass_company_alter_rollingclass_type.py

@@ -0,0 +1,25 @@
+# Generated by Django 4.0.6 on 2022-07-15 15:24
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('metadata', '0004_alter_rollingstocktype_options_and_more'),
+        ('roster', '0006_alter_rollingclassproperty_rolling_class_and_more'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='rollingclass',
+            name='company',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='metadata.company'),
+        ),
+        migrations.AlterField(
+            model_name='rollingclass',
+            name='type',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='metadata.rollingstocktype'),
+        ),
+    ]

ram/roster/models.py

@@ -25,12 +25,8 @@ from metadata.models import (
 
 class RollingClass(models.Model):
     identifier = models.CharField(max_length=128, unique=False)
-    type = models.ForeignKey(
-        RollingStockType, on_delete=models.CASCADE, null=True, blank=True
-    )
-    company = models.ForeignKey(
-        Company, on_delete=models.CASCADE, null=True, blank=True
-    )
+    type = models.ForeignKey(RollingStockType, on_delete=models.CASCADE)
+    company = models.ForeignKey(Company, on_delete=models.CASCADE)
     description = models.CharField(max_length=256, blank=True)
     manufacturer = models.ForeignKey(
         Manufacturer,