void readTransaction(SqlTransactionCallback callback(SqlTransaction transaction), [SqlTransactionErrorCallback errorCallback(SqlError error), VoidCallback successCallback()])

Source 

void readTransaction(SqlTransactionCallback callback, [SqlTransactionErrorCallback errorCallback, VoidCallback successCallback]) {
  if (successCallback != null) {
    _blink.BlinkDatabase.instance.readTransaction_Callback_3_(this, callback, errorCallback, successCallback);
    return;
  }
  if (errorCallback != null) {
    _blink.BlinkDatabase.instance.readTransaction_Callback_2_(this, callback, errorCallback);
    return;
  }
  _blink.BlinkDatabase.instance.readTransaction_Callback_1_(this, callback);
  return;
}