I have a problem with my java apllication that i am unable to create a enitity persistence class..

The problem is that it does not takes the database table for entity class that doesn't have PRIMARY KEY..

I found a way for it by applying PRIMARY KEY as AUTOINCREMENT column..

But, since my application is to be work continuosly with database i cannot estimate a typical auto-increment value limit..

Now what i want is to apply a composit primary key with "date" , "id" column as primary keys together, the "id" must be a AUTO-INCREMENT value that can reset itself from the begening whenever a day changes , i.e, id values resets itself after each day ??

How can i achive this ??
What i tried is like something as follows::

Java Code:
create table test (
id int(4) zerofill auto_increment,
mydate date,
primary key (mydate,id)
);

insert into test (mydate) 
values 
('2011-06-01'),
('2011-06-02'),
('2011-06-02'),
('2011-06-01'),
('2011-06-01'),
('2011-06-03');
But it does not yeild me required result...Any suggestions please????