Basic JDBC transactional question

Question

Hello all,
I have (what I believe) is a basic transactional JDBC question.
Here's what I want to do:
begin transaction
select a row from a table where (some condition).
that row may or may not exist.
if the row exists: update the row
else if the row does not exist, insert a new row
end transaction
I want this entire thing to be atomic .. I don't want the select to complete, then have something else come in there before the update/insert takes place.
I'm using MySQL .. I seem to remember hearing about some proprietary MySQL command which would do a SELECT + UPDATE atomically .. which would be fine, but I can't find it.
Wrapping this with a row-level lock would be fine too .. I'm just not sure how to do that in JDBC.
Thanks!
-d

Answer 1

By thte way, and not that it helps the orignal poster, who's using MySQL, but Oracle has a proprietary MERGE statement that does "insert or update" in one go. For example:
MERGE INTO bonuses D
   USING (SELECT employee_id, salary, department_id FROM employees
   WHERE department_id = 80) S
   ON (D.employee_id = S.employee_id)
   WHEN MATCHED THEN UPDATE SET D.bonus = D.bonus + S.salary*.01
     DELETE WHERE (S.salary > 8000)
   WHEN NOT MATCHED THEN INSERT (D.employee_id, D.bonus)
     VALUES (S.employee_id, S.salary*0.1)
     WHERE (S.salary <= 8000);