onDbDowngrade method

Implementation

FutureOr<void> onDbDowngrade(
  Database db,
  int oldVersion,
  int newVersion,
) async {
  // Run the CREATE TABLE statement on the database.
  await db.transaction((txn) async {
    final batch = txn.batch();
    final allQueries = <String>[];
    for (final element in tables) {
      final queries = element.downgradeTable(oldVersion, newVersion);
      if (queries.isNotEmpty == true) {
        allQueries.addAll(queries);
        for (final query in queries) {
          batch.execute(query);
        }
      }
    }
    await batch.commit(noResult: true);
    _logBatchResult(
      'onDbDowngrade',
      allQueries,
      'Database downgraded from $oldVersion to $newVersion',
    );
  });
  await db.transaction((txn) async {
    final batch = txn.batch();
    final allQueries = <String>[];
    for (final element in tables) {
      final queries = element.onDowngradeComplete(oldVersion, newVersion);
      if (queries.isNotEmpty == true) {
        allQueries.addAll(queries);
        for (final query in queries) {
          batch.execute(query);
        }
      }
    }
    await batch.commit(noResult: true);
    _logBatchResult('After onDbDowngrade', allQueries, null);
  });
}