Reset schema when validateDatabaseSchema() fails

[hiroshihorie]

I use Drift as a local cache for my app and I can afford to clear / recreate all data when schema changes.
How can I reset schema at launch if validateDatabaseSchema() fails and continue to run the app ?

[simolus3]

Something like this in the MigrationStrategy should work:

}, beforeOpen: (details) async {
  try {
    await validateDatabaseSchema();
  } on SchemaMismatch {
    // Delete all databases and re-create
    final migrator = createMigrator();
    final reversedEntities = allSchemaEntities.toList().reversed;

    for (final entity in reversedEntities) {
      await migrator.drop(entity);
    }

    await migrator.createAll();
  }
});

You don't need an onUpgrade callback at all in that case.

[hiroshihorie]

Thanks! But unfortunately I found out that validateDatabaseSchema() might not work with Web, am I correct ?
If so, do you have an alternative idea ?

[simolus3]

Yeah, unfortunately validateDatabaseSchema() does not currently work with web databases because it uses the native sqlite3 APIs to create another database to compare the two.

If so, do you have an alternative idea ?

You could raise the schemaVersion getter after making changes and then use MigrationStrategy get migration => destructiveFallback, which resets the database when onUpgrade is called.

[hiroshihorie]

Thanks, so I guess I will still need to bump the schemaVersion manually.