deleteDatabase method
Implementation
Future<void> deleteDatabase(String password) async {
var db = await _getDb('fhir.db', password);
await db.close();
final appDocDir = await getApplicationDocumentsDirectory();
await File(join(appDocDir.path, 'fhir.db')).delete();
// Setting the completer to null will lead to
// creating a new database the next time we try to access it.
_dbOpenCompleter = null;
}