Constraint on null cost centres

core/migrations/0019_remove_attrition_unique_attrition_and_more.py

@@ -0,0 +1,26 @@
+# Generated by Django 5.1.3 on 2024-12-10 15:04
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("core", "0018_alter_attrition_cost_centre_and_more"),
+        ("costcentre", "0008_alter_simplehistoryarchivedcostcentre_options_and_more"),
+    ]
+
+    operations = [
+        migrations.RemoveConstraint(
+            model_name="attrition",
+            name="unique_attrition",
+        ),
+        migrations.AddConstraint(
+            model_name="attrition",
+            constraint=models.UniqueConstraint(
+                fields=("financial_year", "cost_centre"),
+                name="unique_attrition",
+                nulls_distinct=False,
+            ),
+        ),
+    ]

core/models.py

@@ -134,6 +134,7 @@ class Meta:
                     "financial_year",
                     "cost_centre",
                 ],
+                nulls_distinct=False,
                 name="unique_attrition",
             ),
         )