if(QSqlDatabase::database().transaction()){

                    bool res1,res2;

                    query.prepare("update booklist set borrowNum=?,restNum=? where bookId=?");

                    query.bindValue(,++borrownum);

                    query.bindValue(,--restnum);

                    query.bindValue(,bookId);

                    res1=query.exec();

                    //qDebug()<<"insert "<<res1;

                    query.prepare("insert into recordlist(bookId,bookName,borrowPeople,borrowTime,backTime,\

                                  backState) values(?,?,?,?,?,?)");

                    query.bindValue(,bookId);

                    query.bindValue(,bookName);

                    query.bindValue(,userName);

                    query.bindValue(,borrowTime);

                    query.bindValue(,"");

                    query.bindValue(,);

                    res2=query.exec();

                     //qDebug()<<query.lastError();

                    //qDebug()<<"insert "<<res2;

                    if(res1&&res2){

                        if(!QSqlDatabase::database().commit()){

                            QMessageBox::critical(this,"Error","操作失败，将要回滚");

                            if(!QSqlDatabase::database().rollback()){

                                QMessageBox::critical(this,"Error","回滚失败");

                            }

                        }else{

                            doShowBackResult();

                            //qDebug()<<"show ";

                        }

                    }else{

                        qDebug()<<query.lastError();

                        QMessageBox::critical(this,"Error","操作失败，将要回滚");

                        if(!QSqlDatabase::database().rollback()){

                            QMessageBox::critical(this,"Error","回滚失败");

                            qDebug()<<QSqlDatabase::database().lastError();

                        }

                    }

                }