This will only work if the
*select for update*
and the actual
*update*
are in the same transaction, which I would recommend be done in the same
'trip'
SELECT FOR UPDATE * FROM MYTABLE WHERE MYID=something;
UPDATE .... WHERE MYID=something;
I wouldn't go for a Stateful Session Bean Initiating the transaction with
the first select
and then updating in other trip, because it could lead to deadlocks, racing
conditions, and specially poor
perfomance, as a select for update produces some locking (actually, it's
versioning in Oracle
,so maybe it's not such a bad idea after all)
I'll get back to y'all with this...
HTH
Rifle
-----Original Message-----
From: Bhattacharyya, Ana [mailto:[EMAIL PROTECTED]]
Sent: Thursday, July 13, 2000 4:05 PM
To: [EMAIL PROTECTED]
Subject: Re: Serialized Access
can u give me an example query which uses that?
TIA
Anamitra
-----Original Message-----
From: Juan Pablo Lorandi [mailto:[EMAIL PROTECTED]]
Sent: Thursday, July 13, 2000 3:03 PM
To: [EMAIL PROTECTED]
Subject: Re: Serialized Access
This will only work in Oracle 7 and above AFAIK
Rifle
-----Original Message-----
From: Bhattacharyya, Ana [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, July 12, 2000 6:33 PM
To: [EMAIL PROTECTED]
Subject: Re: Serialized Access
this one is new to me! what is this "for update" clause? and how do u use it
in a select clause? is it databse specific.
TIA
Anamitra
-----Original Message-----
From: Victor Langelo [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, July 12, 2000 5:14 PM
To: [EMAIL PROTECTED]
Subject: Re: Serialized Access
"Bhattacharyya, Ana" wrote:
> also I cannot
> do this check in two queries (first check the timestamp and then update)
as
> they cannot be made atomic.
> correct me if I am wrong.
>
You use the for update clause when selecting the timestamp value. This will
lock
the record.
--Victor
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