Hibernate 3

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();