diff --git a/lib/database/database.dart b/lib/database/database.dart
index 0fdf31b..f6e5649 100644
--- a/lib/database/database.dart
+++ b/lib/database/database.dart
@@ -23,9 +23,11 @@ class AppDatabase extends _$AppDatabase {
   @override
   MigrationStrategy get migration => MigrationStrategy(
     onCreate: (Migrator m) async {
-      // cloudRideId is part of the generated Drift schema. Do not manually
-      // ALTER this column here: generated sources are authoritative for fresh DBs.
       await m.createAll();
+      // cloudRideId is generated by Drift on fresh databases. The uniqueness
+      // constraint is kept as an explicit index so the nullable migration
+      // column remains compatible with older generated source versions.
+      await customStatement('CREATE UNIQUE INDEX IF NOT EXISTS rides_cloud_ride_id_idx ON rides(cloud_ride_id)');
     },
     onUpgrade: (Migrator m, int from, int to) async {
       if (from < 2) {
@@ -77,7 +79,7 @@ class AppDatabase extends _$AppDatabase {
         // Existing MotorCloud records were keyed by the deterministic legacy
         // identity ride_<localId>_<UTC yyyyMMdd_HHmmss>. Preserve that identity
         // for pre-v6 rides so their cloud records remain addressable. New rides
-        // receive an reinstall-safe random stable ID in startRide().
+        // receive a reinstall-safe random stable ID in startRide().
         final rows = await customSelect('SELECT id, start_time FROM rides WHERE cloud_ride_id IS NULL').get();
         for (final row in rows) {
           final id = row.data['id'];