hibernate-HQL-17

最新推荐文章于 2018-10-05 22:37:28 发布

大玉莞尔

最新推荐文章于 2018-10-05 22:37:28 发布

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分类专栏： hibernate 文章标签： hibernate

本文链接：https://blog.youkuaiyun.com/apple_5/article/details/72855625

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本文提供了多个HQL查询示例，包括计数、聚合函数使用、范围查询、列表查询及非空查询等，并展示了如何利用SessionFactory进行数据库操作。

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public class HQLTwoTest {
    public static SessionFactory sf = null;

    @BeforeClass
    public static void beforeClass(){
        Configuration cfg = new AnnotationConfiguration();
        sf = cfg.configure().buildSessionFactory();
    }

    // 注意uniqeResult的使用
    @Test
    public void testHQL_15(){
        Session session = sf.getCurrentSession();
        session.beginTransaction();
        Query q = session.createQuery(" select count(*) from Msg m ");
        long count = (Long)q.uniqueResult();
        System.out.println(count);
        session.getTransaction().commit();
    }

    @Test
    public void testHQL_16(){
        Session session = sf.getCurrentSession();
        session.beginTransaction();
        Query q = session.createQuery(" select max(m.id),min(m.id),avg(m.id),sum(m.id) from Msg m");
        Object[] o = (Object[])q.uniqueResult();
        System.out.println(o[1]+"-"+o[1]+"-"+o[2]);
        session.getTransaction().commit();
    }

    @Test
    public void testHQL_17(){
        Session session = sf.getCurrentSession();
        session.beginTransaction();
        Query q = session.createQuery("  from Msg m where m.id between 3 and 5");
        List<Msg> msgs = (List<Msg>)q.list();
        for(Msg m:msgs){
            System.out.println(m.getCont());
        }
        session.getTransaction().commit();
    }

    @Test
    public void testHQL_18(){
        Session session = sf.getCurrentSession();
        session.beginTransaction();
        Query q = session.createQuery("  from Msg m where m.id in(3,4,5) ");
        List<Msg> msgs = (List<Msg>)q.list();
        for(Msg m:msgs){
            System.out.println(m.getCont());
        }
        session.getTransaction().commit();
    }

    @Test
    public void testHQL_19(){
        Session session = sf.getCurrentSession();
        session.beginTransaction();
        Query q = session.createQuery("  from Msg m where m.id is not null ");
        List<Msg> msgs = (List<Msg>)q.list();
        for(Msg m:msgs){
            System.out.println(m.getCont());
        }
        session.getTransaction().commit();
    }

    @Test
    public void testSchemaExport(){
        //  true  是否将建表语句输出到控制台   true  是否在数据库中建表
        new SchemaExport(new AnnotationConfiguration().configure()).create(true,true);
    }


    @AfterClass
    public static void AfterClass(){
        sf.close();

    }

}