Thankx for the prompt replies.Can any body throw some light on this w.r.t Weblogic 6.
>From: Krishnan Subramanian <[EMAIL PROTECTED]> >Reply-To: Krishnan Subramanian <[EMAIL PROTECTED]> >To: [EMAIL PROTECTED] >Subject: Re: EJB - Primary Key >Date: Thu, 7 Mar 2002 09:10:36 +0100 > >That's where the transaction commit options (A, B & C) defined >in the EJB spec (1.1 and 2.0) come in. I can at least explain >how things work with our Container. > >If you use transaction commit mode B (which is pretty much the >default that most application servers use for entity beans - at >least for us :), then bean instances are put back in the cache >as opposed to the pool. The difference here is that instances >in the cache are associated with their pk (and maybe state - that >is, state of the persisted fields if you use Option A). So at >the start of a transaction when using option B, the Container >already knows the identity of that instance by virtue of its >primary key. So the Container can avoid moving an instance from >the pool ( which contains arbitrary instances; that is, instances >not associated with a pk) and associating it with the pk and instead >only call the ejbLoad() to move that instance in the cache to >the 'ready state'. > >If there is no instance in the cache (we fill it lazily), then >an instance is transitioned out of the pool, associated with >an identity - its pk - and finally followed by a call to the >ejbLoad() to move to the 'ready state'. > >At the end of the transaction, bean instances could move from >the 'ready state' back to the cache or pool depending on the >limits set by the deployer for the number of instances possible >in the cache & pool. > >In Option C, there is no cache - that is, there is only a pool. > >With Option A, at least in our AppServer, the AppServer could >act as a pure middle tier data cache. Since the AppServer has >exclusive access to the database, the instance is not only >associated with its pk but also its state. Thus if an instance >is present in the cache, then the Container can avoid an ejbLoad >(and even an ejbStore() if no modification took place). > >-krish > > > -----Original Message----- > > From: A mailing list for Enterprise JavaBeans development > > [mailto:[EMAIL PROTECTED]]On Behalf Of ejblist ejb > > Sent: Thursday, March 07, 2002 12:06 AM > > To: [EMAIL PROTECTED] > > Subject: EJB - Primary Key > > > > > > Hi : > > > > I was just reading the EJB Specs and was just wondering about the >primary > > key concept.Lemme Give you the scenario which i was thinking. > > > > 1. Let's say we create an Entity bean do some business operations and >log > > out of the system. > > 2. Again we get a reference of the previously created bean using the > > home.findByPK() method which returns me the stub of the remote interface >for > > further operations. > > > > Is it that the container goes to the pool (let's assume the ejb instance >is > > returned back to the pool) picks up any arbitrary bean instance, queries >the > > Datastore, get the data, initialize my bean instance,attach the instance > > with the remote object or is there any other flow of the process. > > I just want to know the internals as to what actually goes behind the >scene. > > > > Thankx > > > > > > _________________________________________________________________ > > MSN Photos is the easiest way to share and print your photos: > > http://photos.msn.com/support/worldwide.aspx > > > > >=========================================================================== > > 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". > _________________________________________________________________ Chat with friends online, try MSN Messenger: http://messenger.msn.com =========================================================================== 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".
