Re: Unknown SQL

Vadim Tropashko wrote:
> Which prompts a natural question "how easy are aggregate/group by queries
 in
> object querying"? Last time your example with car and wheels gave us some
> flavour what object querying is. How about
>
> select sum(sal) from emp group by dept

Hi Vadim,

this is a very simple and good example where a flat, textual representation of data seems to beat objects. I wonder why none of the other gurus here has come up with the question yet.

An instant approach for the current API: sum() and groupBy() would be methods in the Query interface. The resultset (ObjectSet) would contain objects of the class sal (Integer or Double I suppose). This example could still be evaluated within the database engine without the instantiation of objects, so it would be performant.

Now lets make it more complex:
select sum(sal), dept from emp group by dept Here your resultset would contain Objects of the class Object[] (object array).
Object[0] would contain the sum.
Object[1] would contain dept.

Does this sound feasible?

Thanks a lot for the comment.

Kind regards,
Carl

---
Carl Rosenberger
db4o - database for objects - http://www.db4o.com