+++在映射文件中定義命名查詢
<class .. >
</class>
<query name="findCustomersByName"><![CDATA[
    from Customer c where c.name like :name
]]></query>
語句:Query q=session.getNamedQuery("findCustomersByName");
     q.setString("name",name);
     List result=query.list();
++++ HQL Vs QBC 檢索方式

比較運算
1  . 檢索年齡大于18的Customer
     HQL  session.createQuery("from Customer cwhere c.age>18");
     QBC  Criteria criteria=session.createCriteria(Customer.class);
          criteria.add(Expression.gt("age",18));
2 . 檢索年齡不等于 18的
    HQL session.createQuery("from Customer c where c.age<>18")
    QBC Criteria criteria =session.createCriteria(Customer.class);
        criteria.add(Expression.not(Expression.eq("age",new Integer(18))));
3.  檢索姓名為空的Customer對象
   HQL  session.createQuery("from Customer c where c.name is null");
   QBC  Criteria criteria =session.createCriteria(Customer.class);
        criteria.add(Expression.isNull("name"));
4. 檢索不屬于任何客戶的訂單
   HQL  session.createQuery("from Order o where o.customer is null");
   QBC  Criteria criteria =session.createCriteria(Order.class);
        criteria.add(Expression.isNull("customer"));
5. HQL  Query q=session.createQuery("from Customer c where lower(c.name)='tom'");
        Query q=session.createQuery("from Customer c where upper(c.name)='TOM'");
   QBC  Criteria criteria =session.createCriteria(Customer.class);
        criteria.add(Expression.eq("name","tom").ignoreCase());
范圍運算
1. 檢查姓名為 Tom,Mike 或者Jack 的 Customer對象
    HQL session.createQuery("from Customer c where c.name in('Tom','Mike','Jack')");
    QBC Criteria criteria=session.createCriteria(Customer.class);
         String names[]={"Tom","Mike","Jack"};
         criteria.add(Expression.in("name",names));
2. 檢查年齡在 18 到  25之間的Customer對象
   HQL session.createQuery("from Customer c where c.age between 18 and 25");
   QBC Criteria criteria=session.createCriteria(Customer.class);
       criteria.add(Expression.between("age",new Integer(18),newInteger(25)))
3. 檢索年齡不在 18到  25之間的Customer對象;
   HQL session.createQuery("from Customer c where c.age not between 18 and 25");
   QBC Criteria criteria=session.createCriteria(Customer.class);
       criteria.add(Expression.not(Expression.between("age",new Integer(18),newInteger(25))))
字符串模式匹配
1. 檢索姓名以 "T"開頭的Customer對象
     HQL  session.createQuery("from Customer cwhere c.name like 'T%'");
     QBC  Criteria criteria=session.createCriteria(Customer.class);
          criteria.add(Expression.like("name","T%"));
           %表示  任意個字符
           _表示  一個字符
          Or
         criteria.add(Expression.like("name","T",MatchMode.START));
      MatchMode 類中有：
                       START    開頭
                       END      結尾
                       ANYWHERE 包含
                       EXACT    精確
邏輯運算符
  Expression.and(Expression1,Expression2);
  Expression.or(Expression1,Expression2);
  
連接查詢：：：：：
1 . 映射文件中的配置
lazy="true" 延遲加載
fetch="select" 迫切加載
2.
  2.1  迫切左外連接, HQL : from Customer c left join fetch c.orders o where c.name like 'T'");
                   QBC : criteria.setFetchMode("orders",FetchMode.EAGER); 迫切加載
     QBC 只支持 迫切左外連接，與內連接
  2.2  左外連接,    HQL : from Customer c left join c.orders where c.name like 'T%'
                    
  2.3 內連接     HQl :  from Customer c inner join c.orders o where c.name like 'T%'
          
  
2.4 迫切內連接 ,  HQL:  from customer c inner join fetch c.orders o where c.name like 'T%'
2.5 隱式內連接 , HQL :  from customer c where c.homeAddress.provice like '%hai'
2.6 右外連接  ，   HQL :  from customer right outer join c.orders o where c.name like 'T%'

報表查詢 :
   select new mypack.CustomerRow(c.id,c.name,o.orderNumber)
   from customer c join c.orders o
   where o.orderNumber like 'T%'

   distinct 關鍵字 消除重復關鍵字
   order by  asc||desc 排序
   group by 列    分組查詢