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From Dyre.Tjeldv...@Sun.COM
Subject Re: rows locking in derby
Date Mon, 29 Jan 2007 14:11:48 GMT
Cristian Dudila <cristian.dudila@keats-software.com> writes:

> Hi,
>
>   We use derby for an application and we need to lock some rows. The
> problem is that we would like to know if this rows are already locked.
> Using TRANSACTION_REPEATABLE_READ we can lock this rows ( using SELECT
> )but we don't know if this rows was already locked. Using "SELECT FOR
> UPDATE" derby returns an exception that tell us that the row is
> locked, but unfortunately ( for us ) we can lock only one row using
> "SELECT FOR UPDATE".

I think it would be better if you could describe what it is you're
trying to achieve. 

> Is there a possibility to lock multiple rows, using one connection and
> to receive an exception or message ( from derby ) if this rows are
> locked by somebody else before ?

Maybe I don't understand what you're trying to do, but in general it
is not a good idea to use the database to communicate between
threads. The database tries its best to hide the fact that other
threads (connections) are accessing the data.

-- 
dt


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