Hibernate查询

目标 ,[object Object],[object Object],[object Object]

Hibernate 基本查询 ,[object Object],[object Object],[object Object]

使用 get 方法 ,[object Object],[object Object]

使用 createQuery 方法 ,[object Object]

配置查询条件 ,[object Object],[object Object],<query name="onlyfun.caterpillar.queryUser"> <![CDATA[ select user.name from User as user where user.age = :age and user.sex = :sex ]]> </query>

使用配置查询 ,[object Object],Query query = session.getNamedQuery("onlyfun.caterpillar.queryUser"); query.setInteger("age", 25); query.setCharacter("sex", 'M'); List names = query.list(); }

Hibernate 语言查询 ,[object Object],[object Object],[object Object],[object Object],[object Object]

HQL ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

使用 HQL ,[object Object],[object Object],[object Object],[object Object],[object Object]

实体查询 ,[object Object],[object Object],[object Object],String hql=”from User user ”; List list=session.CreateQuery(hql).list(); 持久类别名 from User user where user.age=20; from User user where user.age between 20 and 30; from User user where user.age in(20,30); from User user where user.name is null; from User user where user.name like ‘%zx%’; from User user where (user.age%2)=1; from User user where user.age=20 and user.name like ‘%zx%’;

实体的更新和删除 ,[object Object],[object Object],Transaction trans=session.beginTransaction(); String hql=”update User user set user.age=20 where user.age=18”; Query queryupdate=session.createQuery(hql); int ret=queryupdate.executeUpdate(); trans.commit(); Transaction trans=session.beginTransaction(); String hql=”delete from User user where user.age=18”; Query queryupdate=session.createQuery(hql); int ret=queryupdate.executeUpdate(); trans.commit();

属性查询 ,[object Object],[object Object],[object Object],List list=session.createQuery(“select user.name from User user ”).list(); List list=session.createQuery(“select user.name,user.age from User user ”).list(); List list=session.createQuery(“select new User(user.name,user.age) from User user ”).list(); 注意，这时所返回的 User 对象，仅仅只是一个普通的 Java 对象而以，除了查询结果值之外，其它的属性值都为 null （包括主键值 id ），也就是说不能通过 Session 对象对此对象执行持久化的更新操作 , 只能 save()

分组与排序 ,[object Object],[object Object],[object Object],from User user order by user.name asc,user.age desc; String hql=”select count(user),user.age from User user group by user.age having count(user)>10 ”; List list=session.createQuery(hql).list();

优化统计查询 from Customer c inner join c.orders o group by c.age;(1) select c.ID,c.name,c.age,o.ID,o.order_number,o.customer_ID from Customer c inner join c.orders o group by c.age;(2) 语句（ 1 ）检索的结果会返回 Customer 与 Order 持久化对象，而且它们会被置于 Hibernate 的 Session 缓存之中 , 只有事务提交后它们才会从缓存中被清除语句（ 2 ）返回的是关系数据而并非是持久化对象，因此它们不会占用 Hibernate 的 Session 缓存，只要在检索之后应用程序不在访问它们，它们所占用的内存就有可能被 JVM 的垃圾回收器回收，而且 Hibernate 不会同步对它们的修改尽量使用通过 select 语句写出需要查询的属性的方式来返回关系数据 , 而避免使用第一种查询方式返回持久化对象（这种方式是在有修改需求时使用比较适合），这样可以提高运行效率并且减少内存消耗 name varchar2(20) age number(10) ID varchar2(14) customer customer_ID varchar2(14) order_number number(10) ID varchar2(14) order

参数绑定 ,[object Object],PrepareStatement pre=connection.prepare(“select * from User where user.name=?”); pre.setString(1,”zhao”); ResultSet rs=pre.executeQuery();

参数绑定 ,[object Object],[object Object],[object Object],Query query=session.createQuery(“from User user where user.name=:customername and user.age=:customerage”); query.setString(“customername”,name); query.setInteger(“customerage”,age); Query query=session.createQuery(“from User user where user.name=? and user.age =? ”); query.setString(0,name); query.setInteger(1,age);

参数绑定 ,[object Object],[object Object],[object Object],String hql=”from User user where user.name=:customername ”; Query query=session.createQuery(hql); query.setParameter(“customername”,name,Hibernate.STRING);

参数绑定 ,[object Object],[object Object],Customer customer=new Customer(); customer.setName(“pansl”); customer.setAge(80); Query query=session.createQuery(“from Customer c where c.name=:name and c.age=:age ”); query.setProperties(customer);

使用绑定参数的优势 ,[object Object],[object Object]

构建 Criteria 查询 ,[object Object],[object Object],[object Object],Criteria criteria = session.createCriteria(User.class); // 查询 user 所有字段 List users = criteria.list(); Iterator iterator = users.iterator(); System.out.println("id name/age"); while(iterator.hasNext()) { User user = (User) iterator.next(); System.out.println(user.getId() + " " + user.getName() + "/" + user.getAge()); }

构建 Criteria 查询 ,[object Object],[object Object],Criteria criteria = session.createCriteria(User.class); criteria.add(Restrictions.gt("age", new Integer(20))); criteria.add(Restrictions.lt("age", new Integer(40))); List users = criteria.list();

使用逻辑组合来进行查询 ,[object Object],Criteria criteria = session.createCriteria(User.class); criteria.add(Restrictions.or( Restrictions.eq("age", new Integer(20)), Restrictions.isNull("age") )); List users = criteria.list();

SQL 语法作限定查询 ,[object Object],[object Object],Criteria criteria = session.createCriteria(User.class); criteria.add(Restrictions.sqlRestriction(“{ 类名 }.name LIKE (?)", "cater%", Hibernate.STRING)); List users = criteria.list(); 其中 ? 将被替换为 cater% Criteria criteria = session.createCriteria(User.class); Integer[ ] ages = {new Integer(20), new Integer(40)}; Type[ ] types = {Hibernate.INTEGER, Hibernate.INTEGER}; criteria.add(Restrictions.sqlRestriction("{alias}.age BETWEEN (?) AND (?)", ages, types)); List users = criteria.list();

Restrictions 常用限定查询方法 ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

Criteria 高级特性 ,[object Object],Criteria criteria = session.createCriteria(User.class); // 限定查询返回检索结果中，从第一百条结果开始的 20 条记录 criteria.setFirstResult(100); criteria.setMaxResults(20);

Criteria 高级特性 ,[object Object],// 查询所有 groupId=2 的记录 // 并分别按照姓名 ( 顺序 ) 和 groupId （逆序）排序 Criteria criteria = session.createCriteria(TUser.class); criteria.add(Expression.eq("groupId",new Integer(2))); criteria.addOrder(Order.asc("name")); criteria.addOrder(Order.desc("groupId"));

Criteria 和 DetachedCriteria ,[object Object],[object Object]

Hibernate查询

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