Posted on 2007-08-24 16:36
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hibernate
1。文件的映射。由于使用 MyEclipse（傻瓜版^_^） 所以 hibernate工具（extensions，Middlegen，tools等）一直没好好研究这就不献丑了。
2。Criteria
1）查询条件通过 Criteria.add 添加 Expression 用于描述条件
Expression.( and or like in le lt ..... )
参见：
Criteria查询 2）criteria.setFirstResult(100);
criteria.setMaxResults(20);
//检索范围
criteria.addOrder(Order.asc("name")); //排序 .add( Expression.sql("lower($alias.name) like lower(?)", "Fritz%", Hibernate.STRING)
//直接嵌入SQL
3）Cat cat = new Cat();
....
List results = session.createCriteria(Cat.class).add( Example.create(cat) ).list();
//根据对象查询 3。HQL 完全面向对象的，具备继承、多态和关联等特性。
1）参见：
HQL 2）内连接，inner join
左外连接，left outer join
右外连接，right outer join http://www.hibernate.org/hib_docs/reference/en/html/queryhql.html
代表性的语句 Hql.hbm.xml
<set name="fkSet" inverse="true">
<key column="id"/>
<one-to-many class="Fk"/>
</set>
SQL
alter table fk add constraint FK_hf foreign key(id) references hql(id)
mysql> select * from hql;
+----+----------+
| id | name |
+----+----------+
| 0 | liukaiyi |
| 1 | heha |
+----+----------+
2 rows in set (0.00 sec)
mysql> select * from fk;
+----+------+
| id | name |
+----+------+
| 0 | yy |
| 1 | xx |
+----+------+
2 rows in set (0.00 sec)
//简单的 结果： 2 liukaiyi:heha
Query qu = se.createQuery("select h.name " +
" from Hql h , Fk f" +
" where h.id = f.id" );
List list = qu.list() ;
tr.commit();
System.out.println( list.size() );
System.out.println( list.get(0)+":"+list.get(1) );
//给出对象 结果 : hehaQuery qu = se.createQuery("from Hql h where h.fkSet.name='xx'");
((Hql)list.get(0)).getName() ;
//给出Object 结果：heha xxQuery qu = se.createQuery("select h.name,f.name from Hql h join h.fkSet f where f.name='xx'");
List list = qu.list() ;
tr.commit();
System.out.println(list.size());
Object[] objs = (Object[]) list.get(0) ;
System.out.println( objs[0] +":"+objs[1] );
//给出 Map heha xx
Query qu = se.createQuery("select new map( h.name as hn,f.name as fn)from Hql h join h.fkSet f where f.name='xx'");
List list = qu.list() ;
tr.commit();
System.out.println(list.size());
Map map = ((Map)list.get(0));
System.out.println( map.get("hn") );
}
//报表语句 结果: 1 Query qu = se.createQuery("select count(*) from Hql h join h.fkSet f " +
" where h.name='heha' and h.id=f.id " +
" group by h.name ");
List list = qu.list() ;
tr.commit();
System.out.println( list.get(0) );
//集合内 结果 liukaiyi:heha
//元素集(elements与indices 函数) 可以使用 any, some, all, exists, in
//EG: from Player p where 3 > all elements(p.scores) +----+----------+
| id | name |
+----+----------+
| 0 | liukaiyi |
| 1 | heha |
| 3 | oo |
+----+----------+
Query qu = se.createQuery("select h.name " +
" from Hql h" +
" where h.id in elements(h.fkSet.id) " );
List list = qu.list() ;
tr.commit();
System.out.println( list.get(0)+":"+list.get(1) );
//使用 javaBean 绑定
Query q = s.createQuery("from foo Foo as foo where foo.name=:name and foo.size=:size");
q.setProperties(fooBean); // fooBean包含方法getName()与getSize()
List foos = q.list();