Hibernate HQL语句使用总结

//直接from查询出来的是一个映射对象，即：查询整个映射对象所有字段  


        String hql =
"from Users";  

        Query query = session.createQuery(hql);  


        List<Users> users = query.list();  


        for(Users user : users){  


            System.out.println(user.getName() +
" : " + user.getPasswd() +
" : " + user.getId());  


        }  


 输出结果为：  


name1 : password1 :
1

name2 : password2 :
2

name3 : password3 :
3

//查询其中几个字段  

        String hql =
" select name,passwd from Users";  


        Query query = session.createQuery(hql);  


        //默认查询出来的list里存放的是一个Object数组  


        List<Object[]> list = query.list();  


        for(Object[] object : list){  


            String name = (String)object[0];  


            String passwd = (String)object[1];  


            System.out.println(name +
" : " + passwd);  


        }  


输出结果为：  

name1 : password1  


name2 : password2  


name3 : password3 


//查询其中几个字段,添加new list(),注意list里的l是小写的。也不需要导入包，这样通过query.list()出来的list里存放的不再是默认的Object数组了，而是List集合了 


         String hql =
" select new list(name,passwd) from Users";  


        Query query = session.createQuery(hql);  


        //默认查询出来的list里存放的是一个Object数组，但是在这里list里存放的不再是默认的Object数组了，而是List集合了  


        List<List> list = query.list();  


        for(List user : list){  


            String name = (String)user.get(0);  


            String passwd = (String)user.get(1);  


            System.out.println(name +
" : " + passwd);  


        }  


        /** 


        输出结果为： 


         name1 : password1 


        name2 : password2 


        name3 : password3 


         */

//查询其中几个字段,添加new map(),注意map里的m是小写的。也不需要导入包，这样通过query.list()出来的list里存放的不再是默认的Object数组了，而是map集合了  


        String hql =
" select new map(name,passwd) from Users";  


        Query query = session.createQuery(hql);  


        //默认查询出来的list里存放的是一个Object数组，但是在这里list里存放的不再是默认的Object数组了，而是Map集合了  


        List<Map> list = query.list();  


        for(Map user : list){  


            //一条记录里所有的字段值都是map里的一个元素,key是字符串0,1,2,3....，value是字段值  


            //如果将hql改为：String hql = " select new map(name as username,passwd as password) from Users";,那么key将不是字符串0,1,2...了，而是"username","password"了  


            String name = (String)user.get("0");//get("0");是get(key),注意:0,1,2...是字符串，而不是整形  


            String passwd = (String)user.get("1");  


            System.out.println(name +
" : " + passwd);  


        }  


        /** 


        输出结果为： 


         name1 : password1 


        name2 : password2 


        name3 : password3 


         */

//条件查询，参数索引值从0开始，索引位置。通过setString,setParameter设置参数  


        String hql =
"from Users where name=? and passwd=?";  


        Query query = session.createQuery(hql);  


        //第1种方式  


//      query.setString(0, "name1");  


//      query.setString(1, "password1");  


        //第2种方式  


        query.setParameter(0,
"name1",Hibernate.STRING);  


        query.setParameter(1,
"password1",Hibernate.STRING);  


        List<Users> list = query.list();  


        for(Users users : list){  


            System.out.println(users.getId());  


        }  


//条件查询，自定义索引名(参数名):username,:password.通过setString,setParameter设置参数  


        String hql =
"from Users where name=:username and passwd=:password";  


        Query query = session.createQuery(hql);  


        //第1种方式  


//      query.setString("username", "name1");  


//      query.setString("password", "password1");  


        //第2种方式,第3个参数确定类型  


        query.setParameter("username",
"name1",Hibernate.STRING);  


        query.setParameter("password",
"password1",Hibernate.STRING);  


        List<Users> list = query.list();  


        for(Users users : list){  


            System.out.println(users.getId());  


        } 


//条件查询,通过setProperties设置参数  


        String hql =
"from Users where name=:username and passwd=:password";  


        Query query = session.createQuery(hql);  


        //MyUser类的2个属性必须和:username和:password对应  


        MyUser myUser =
new MyUser("name1","password1");  


        query.setProperties(myUser);  


        List<Users> list = query.list();  


        for(Users users : list){  


            System.out.println(users.getId());  


        } 


String sql="update Table set field = ‘test‘"

Session session = HibernateSessionFactory.getSession();

session.createSQLQuery(sql).executeUpdate();

ts.commit();

String hql="update Table set field = ‘test‘"