really? I'm much afraid that within a given instance of orion, no more than
one instance of any given entity will map to a DB
row. Of course, in a clustered environment with N machines, you'll have at
most N instances of a given entity, in which case your assertions are true
Carlos.
Isolation in transactions has many different variants or levels; check out
orion-ejb-jar.xml for more details.
A select for update is only valid while you still reference the involved
records, i.e.: is valid in this sequence
(CONNECT)
SELECT FOR UPDATE
UPDATE
[COMMIT]
(DISCONNECT)
however with ejb's:
(CONNECT)
SELECT
(DISCONNECT)
...
(CONNECT)
[SELECT [FOR UPDATE]]
UPDATE
[COMMIT]
(DISCONNECT)
transaction context and transaction activity are key concepts in
understanding what is really happening behind the scenes
My 2c,
JP
> -----Original Message-----
> From: Carlos Otero Barros [mailto:[EMAIL PROTECTED]]
> Sent: Martes, 30 de Enero de 2001 18:19
> To: [EMAIL PROTECTED]
> Subject:
>
>
> Hi.
> Not sure what you mean by "SELECT FOR UPDATE".
> Two instances of the same Entity Bean over the same row still
> have different
> transaction contexts.
> You may expect isolation from transactions so you can rely on them.
> If two users try to update the row almost at the same time
> from different
> instances of the same class of Entity Bean then the standard
> transaction
> approach applies.
>
> Regards.
>
> ----- Original Message -----
> From: "manishi tuli" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Tuesday, January 30, 2001 7:53 PM
>
>
> > if 2 instances of ejb are trying to update same row , can
> we handle this
> > thing with ejb transaction or we have to do with select for update
> >
> > thanks
> >
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