TimedObject接口：
    public interface javax.ejb.TimedObject{
    public void ejbTimeout(Timer timer);
    }

……    
    public interface javax.ejb.TimerService{
    public Timer createTimer(java.util.Date expiration,
    java.iO.Serializable info);
    public Timer createTimer(java.util.Date initialExpiration,
    long intervalDuration,java.io.Serializable info);
    public Timer createTimer(long duration,
    java.io.Serializable info);
    public Timer createTimer(long initialDuration,
    long intervalDuration,
    java.io.Serializable info);
    public Collection getTimers();
    }
   ……

SELECT OBJECT(I)
  FROM Users as I
  ORDER BY UID

SELECT DISTINCT I.customer.name
FROM Customer as I
    WHERE I.city=NanJing
    ORDER BY I.customer.name

SELECT COUNT(C)
    FROM Customer as C
    WHERE C.city=NanJing
    下面的例子中，我们可以得到用户工资的总和：
    SELECT SUM(C.totalsalary)
    FROM Customer as C
    WHERE C.city=NanJing