Add migration to set DB constraint

Author: norkans7

ureport/stats/migrations/0032_add_check_constraint.py

@@ -0,0 +1,24 @@
+# Generated by Django 5.2.8 on 2025-11-20 12:35
+
+from django.db import migrations
+
+
+# language=SQL
+CONSTRAINT_SQL_POLLSTATS_ONE_SEGMENT_SET_MAX = """
+ALTER TABLE stats_pollstats ADD CONSTRAINT check_pollstats_only_one_segment_set CHECK (num_nonnulls(age_segment_id, gender_segment_id, location_id, scheme_segment_id) <= 1);
+"""
+
+# language=SQL
+CONSTRAINT_SQL_POLLSTATS_ONE_SEGMENT_SET_MAX_DROP = """
+ALTER TABLE stats_pollstats DROP CONSTRAINT IF EXISTS check_pollstats_only_one_segment_set;
+"""
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("stats", "0031_migrate_poll_stats"),
+    ]
+
+    operations = [
+        migrations.RunSQL(CONSTRAINT_SQL_POLLSTATS_ONE_SEGMENT_SET_MAX, CONSTRAINT_SQL_POLLSTATS_ONE_SEGMENT_SET_MAX_DROP),
+    ]