Hibernate 3-优快云博客

本文介绍了HQL（Hibernate Query Language）的基本操作，包括查询、更新、删除和插入语句的使用方法。通过示例展示了如何利用HQL进行数据检索、更新、删除及新增记录，并演示了如何使用函数、分组及排序等功能。

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Introduction to HQL

1. Select statement : See this, http://blog.sina.com.cn/s/blog_65b4ed520100hbij.html

Session session = sessionFactory.openSession(); Query query = session.createQuery("from User"); List names = query.list(); Iterator iterator = names.iterator(); while(iterator.hasNext()) { User user = (User) iterator.next(); System.out.println(user.getId() + "/t" + user.getAge() + "/t" + user.getName()); }

Session session = sessionFactory.openSession(); Query query = session.createQuery("select user.age, user.name from User as user"); List names = query.list(); Iterator iterator = names.iterator(); while(iterator.hasNext()) { Object[] obj = (Object[]) iterator.next(); System.out.println(obj[0] + "/t" + obj[1]); }

也可以在HQL中使用函式 :

Query query = session.createQuery("select count(*) from User as user");

Query query = session.createQuery("select avg(user.age) from User as user"); List names = query.list(); Iterator iterator = names.iterator(); while(iterator.hasNext()) { System.out.println(iterator.next()); }

Query query = session.createQuery("select upper(user.name) from User as user"); List names = query.list(); Iterator iterator = names.iterator(); while(iterator.hasNext()) { System.out.println(iterator.next()); }

可以使用group by、order by 子句来查询。

Query query = session.createQuery("from User user where (user.age > 20) and (user.name = 'caterpillar')");

Query query = session.createQuery("from User user where user.name is not null");

Query query = session.createQuery("from User user where user.age between 20 and 30");

Query query = session.createQuery("from User user where user.name in('caterpillar', 'momor')");

Query query = session.createQuery("from User user where user.name like 'cater%'");

Query query = session.createQuery("from User user order by user.age");

2.Update statement

Session session = sessionFactory.openSession(); Transaction tx= session.beginTransaction(); Query query = session.createQuery("update User set name='momor' where name='bbb'"); query.executeUpdate(); tx.commit(); session.close();

3.Delete statement

Session session = sessionFactory.openSession(); Transaction tx= session.beginTransaction(); Query query = session.createQuery("delete User where name='bush'"); query.executeUpdate(); tx.commit(); session.close();

4.Insert statement

SessionFactory sf = new Configuration().configure().buildSessionFactory(); Session session = sf.openSession(); Transaction tx = session.beginTransaction(); student st=new student(); st.setId("0001"); st.setUserName("Wang"); st.setpassWord("123"); session.save(st); tx.commit(); session.close();