mysql 更新子查询 mysql更新如果失败怎么处理 – 数据库 – 前端 syscolumns mysql

Release r = dao.findRelease(releaseId); Book b = dao.findBook(bookId); if(r != null && b != null){ Session session = HibernateUtils.getSession(); Transaction tx = session.beginTransaction(); try{dao.cancelBook(r, b); dao.updateReleaseCounts(r, b); }catch(Exception e){tx.rollback(); }mit();}