Chris,
This may be a solution, but a little ugly; a daemon or any trigger will not know
which entity beans are active; we only want to synchronize the active beans. I
think it is proper to let the container to poll the RDBMS, may add an method
"boolean ejbValid()". Any idea?
Lam
Chris Raber wrote:
> EJB is a "pull" rather than a "push" metaphor.
>
> You could have a daemon that polls your RDBMS to instantiate entity beans,
> or some sort of trigger based event queue implementation.
>
> -Chris.
>
> > -----Original Message-----
> > From: Fong Shing Lam [SMTP:[EMAIL PROTECTED]]
> > Sent: Thursday, October 28, 1999 2:29 PM
> > To: [EMAIL PROTECTED]
> > Subject: Re: Q: Multiple EJB servers with one DB
> >
> > This is my question too. Say, if I have a news database that is updated by
> > third party, and want to have a group of entity beans that serve news. In
> > this entity bean class, I would intend to implement only the ejbLoad()
> > method and some bussiness get methods for the session bean which will do
> > whatever it needs with the returned news. For data integrity, I can only
> > rely on a smart container which will get the table modify time frequent
> > enough to invoke my ejbLoad(). This frequency is better configurable to
> > suite my application need.
> >
> > Is this a feature for a general EJB server? or some other smart way to
> > keep the memory in sycn with the underlying DB?
> >
> > Lam
> >
> > Javier Borrajo wrote:
> >
> >
> >
> > Assume there's one (huge) DB to which we want to provide
> > access through EJB.Assume that there're multiple EJB servers that should
> > provide access to this DB.Assume that a row in the DB is represented by an
> > entity bean.Now, if an entity bean has been instantiated at BOTH servers,
> > and then updated from one server, how is the second bean (at the 2nd
> > server) updated? (This is even more problematic if caching is used)
> >
> > I understand second bean only needs to be updated when involved in
> > next transaction,so there is no integrity problem but yes a performance
> > problem. Data caching is only possible/recommended if the EJB server does
> > not sharethe database with any other system, other EJB servers included,
> > unless the vendorimplements multiple node data caching mechanisms. Regards
> > Javier Borrajo www.tid.es <http://www.tid.es>
> >
>
> ===========================================================================
> To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
> of the message "signoff EJB-INTEREST". For general help, send email to
> [EMAIL PROTECTED] and include in the body of the message "help".
===========================================================================
To unsubscribe, send email to [EMAIL PROTECTED] and include in the body
of the message "signoff EJB-INTEREST". For general help, send email to
[EMAIL PROTECTED] and include in the body of the message "help".
