rollback method

Implementation

@override
void rollback() {
  if (active) {
    if (_options.contains(TSQLTransactionOption.stoUseImplicit)) {
      databaseError(SErrImplicitNoRollBack);
    }
    closeDataSets();
    if (logEvent(TDBEventType.detRollBack)) {
      log(TDBEventType.detRollBack, SRollingBack);
    }
    // FTrans=Nil for the case of forced close. (original comment kept as-is)
    if (sqlConnection!.attemptRollBack(_trans!) || _trans == null) {
      closeTrans();
      _trans = null;
    }
  }
}