Hibernate查询1.ppt

* HQL条件查询——范围运算 检索姓名为tom,mike,jack的Customer对象 From Customer c where c.name in(‘tom’,’mike’,’jack’) 检索年龄在18～25之间的Customer对象 From Customer c where c.age between 18 and 25 检索年龄不在18～25之间的Customer对象 From Customer c where c.age not between 18 and 25 * HQL条件查询——模糊查询 检索姓名以T开始的Customer对象 From Customer c where c.name like ‘T%’ 检索姓名中包含字符串“om”的Customer对象 From Customer c where c.name like ‘%om%’ 检索姓名以T开头，并且字符串长度为3的Customer对象 From Customer c where c.name like ‘T_ _’ * HQL条件查询——逻辑运算 检索姓名以T开头，并且以m结尾的Customer对象 From Customer c where c.name like ‘T%’ and c.name like ‘%m’ 检索姓名以T开头，并且以m结尾，或者年龄不在18～25之间的Customer对象 From Customer c where (c.name like ‘T%’ and c.name like ‘%m’) or (c.age not between 18 and 25) * 投影查询——过滤部分字段 返回的List集合元素为Object[] Query query = session.createQuery(select c.cname, c.csex from Customer c); List list = query.list(); For(int i=0;ilist.size();i++) { Object[] ob=list.get(i); } System.out.println(-------------------); } HQL语句是不是有点不一样？ * 分页查询 Query query = session.createQuery(from Customer c); query.setFirstResult(1);//从哪儿开始取 query.setMaxResults(2);//最多取多少条记录 Iterator iter = query.list().iterator(); Customer c = null; while(iter.hasNext()){ c = (Customer) iter.next(); System.out.print(c); } * * * 第一种分析： lazy=“false” outer-join=“false”： 结果： Hibernate: select customer0_.cid as cid0_0_, customer0_.cname as cname0_0_ from Customer customer0_ where customer0_.cid=? Hibernate: select orders0_.cid as cid1_, orders0_.oid as oid1_, orders0_.oid as oid1_0_, orders0_.odate as odate1_0_, orders0_.cid as cid1_0_ from Orders orders0_ where orders0_.cid=? 江和平 第二种分析： lazy=false outer-join=true 结果： Hibernate: select customer0_.cid as cid0_1_, customer0_.cname as cname0_1_, orders1_.cid as cid3_, orders1_.oid as oid3_, orders1_.oid as oid1_0_, orders1_.odate as odate1_0_, orders1_.cid as cid1_0_ from Customer customer0_ left outer join Orders orders1_ on customer0_.cid=orders1_.cid where customer0_.cid=? 江和平 第三种分析： lazy=true outer-join=false“ 结果： Hibernate: select customer0_.cid