Hibernate学习之QBC和本地SQL查询

hibernate 学习之QBC和本地SQL查询

QBC查询是通过使用hibernate提供的QUeryByCriteria API 来查询对象，

这种API封装了SQL语句的动态拼装，对查询提供了更加面向对象的功能接口。

本地SQL查询来完善HQL不能覆盖所有的查询特性

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@Test
public void testQBC() {
//1.创建一个criteria 对象
Criteria criteria = session.createCriteria(Employee.class);
//2. 添加查询条件，在qbc中查询条件使用criterion来表示
//criterion可以通过Restrictions类的静态方法得到
criteria.add(Restrictions.eq("email", "SKUMAR"));
criteria.add(Restrictions.gt("salary", 5000f));

Employee employee = (Employee) criteria.uniqueResult();

System.out.println(employee);

}

@Test
public void testQBC2() {
//1.创建一个criteria 对象
Criteria criteria = session.createCriteria(Employee.class);

//and  的使用  Conjunction 本身就是一个criterion对象，其中还可以添加criterion对象
Conjunction conjunction = Restrictions.conjunction();
conjunction.add(Restrictions.like("name", "a", MatchMode.ANYWHERE));

Department dept = new Department();
dept.setId(20);
conjunction.add(Restrictions.eq("dept", dept));
System.out.println(conjunction);

Disjunction disjunction = Restrictions.disjunction();
disjunction.add(Restrictions.ge("salary", 6000f));
disjunction.add(Restrictions.isNull("email"));

criteria.add(disjunction).add(conjunction);

List list = criteria.list();
System.out.println(list);

}

@Test
public void testQBC3() {
//1.创建一个criteria 对象
Criteria criteria = session.createCriteria(Employee.class);

//统计查询
criteria.setProjection(Projections.max("salary"));

Float o = (Float) criteria.uniqueResult();
System.out.println(o);

}

@Test
public void testQBC4
4000
() {
//1.创建一个criteria 对象
Criteria criteria = session.createCriteria(Employee.class);

//排序
criteria.addOrder(Order.asc("salary"));
criteria.addOrder(Order.desc("email"));

int pageSize = 5;
int pageNo = 3;

criteria.setFirstResult((pageNo - 1) * pageSize)
.setMaxResults(pageSize);
List list = criteria.list();
System.out.println(list);

}

@Test
public void testNativeSql() {
String sql = "INSERT INTO HB_DEPARTMENT VALUES(?, ?)";
Query sqlQuery = session.createSQLQuery(sql);

sqlQuery.setInteger(0, 280).setString(1, "马哥私房菜").executeUpdate();

}

@Test
public void testHQLUpdate(){
String sql = "delete from Department  d where d.id = :id";
Query query = session.createQuery(sql);
query.setInteger("id", 280).executeUpdate();
}