Subselect in EJB 2.1

Question

Hi,
what's the best way to do a query like this
UPDATE
   table
WHERE id = (
   SELECT
      id
   FROM
      table
   WHERE
      <condition>
   ORDER BY id
   LIMIT 1
)in EJB 2.1 while taking into consideration that subselects are not transaction safe? If you have any idea, please tell me :-)
Thanks
-Danny

Answer 1

Hm... looks, better, right! :)
But I guess this can't be done using EJBQL. Is is race condition safe to
write a finder with the join part like this:
SELECT OBJECT(a) FROM tableA AS a, tableB as B
WHERE a.id = b.id AND a.reservedForID = 0 AND b.<col> = <condition>and then do a
TableAValue aVal= aLocal.findBy...();
aVal.setReservedForID(id);
aLocal.update(aVal);without havind a second thread finding the exact same entry? Is it correct,
that the container has to lock the entry that is returned?