Hibernate查询方法之探析-hibernate 查询

1: QBE (Query By Example)

    Criteria cri = session.createCriteria(Student.class);
cri.add(Example.create(s)); //s是一个Student对象
list cri.list();

实质：创建一个模版，比如我有一个表serial有一个 giftortoy字段，我设置serial.setgifttoy("2"),
则这个表中的所有的giftortoy为2的数据都会出来

2: QBC (Query By Criteria) 主要有Criteria,Criterion,Oder,Restrictions类组成

 session = this.getSession();
Criteria cri = session.createCriteria(JdItemSerialnumber.class);
Criterion cron = Restrictions.like("customer",name);
cri.add(cron);
list = cri.list();

比较运算符

HQL运算符 QBC运算符含义
=Restrictions.eq()等于
<> Restrictions.not(Exprission.eq()) 不等于
>Restrictions.gt()大于
>= Restrictions.ge()大于等于
<= Restrictions.le()小于等于
is null Restrictions.isnull() 等于空值
is not nullRestrictions.isNotNull() 非空值
like Restrictions.like() 字符串模式匹配
and Restrictions.and() 逻辑与
and Restrictions.conjunction()逻辑与
or Restrictions.or()逻辑或
or Restrictions.disjunction()逻辑或
notRestrictions.not() 逻辑非
in(列表) Restrictions.in()等于列表中的某一个值
ont in(列表)Restrictions.not(Restrictions.in())不等于列表中任意一个值
between x and yRestrictions.between() 闭区间xy中的任意值
not between x and y Restrictions.not(Restrictions..between()) 小于值X或者大于值y

3: HQL

    String hql = "select s.name ,avg(s.age) from Student s group by s.name";
Query query = session.createQuery(hql);
list = query.list();
....

4: 本地SQL查询

   session = sessionFactory.openSession();
tran = session.beginTransaction();
SQLQuery sq = session.createSQLQuery(sql);
sq.addEntity(Student.class);
list = sq.list();
tran.commit();

5: QID

Session的get()和load()方法提供了根据对象ID来检索对象的方式。该方式被用于事先知道了要检索对象ID的情况。

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