That is exactly what I was looking for. Thanks again for a great tool.
Regards, John -----Original Message----- From: Gavin King [mailto:[EMAIL PROTECTED] Sent: Saturday, October 18, 2003 6:06 AM To: Urberg, John Cc: '[EMAIL PROTECTED]' Subject: Re: [Hibernate] Saving Collections from Multiple Sessions You need to upgrade to Hibernate 2.1, and understand the select-before-update mapping attribute. Urberg, John wrote: >Hibernate also seems to always assume objects from different sessions are >dirty. (I'm using saveOrUpdate() in 1.2.5. Maybe this has changed in 2.*?) > >Anyway, I need to work around this to be able to use Hibernate in a 3-tier >system. I can only have SQL created when an object is really dirty since >there are triggers in the database. So here are the changes I think could >accomplish my goals: > >1) Upgrade to 2.* so I can use the latest features on the Interceptor >2) Add code to handle unsaved-values correctly on objects with >composite-ids. >3) Modify SessionImpl to bypass Collection updating in >removeCollectionsFor() and prepareCollectionsForUpdate() (I mentioned this >in the last post). >4) Add a method to our base Domain Object class to return dependent objects. >Each domain object class will then need to return the collections of objects >that need to get updated when it is updated. This will be a manual work >around for cascading on collections since I disabled that in step #3 >5) Modify my transaction management code to set WAIT_FOR_COMMIT = true >during the transactions since we can't control the order dependent objects >get because of #3 & #4. >6) Add methods to our base Domain Object class to capture the original value >of a property when it changes. The Domain Object class will then have a has >map with the original values of only the properties that changed. If the >map is empty, the object is not dirty. >7) In Intercepter.findDirty(), determine the properties that changed based >on #6. > >If this works, the only changes I'd have to make in Hibernate proper would >be a switch to disable the collections stuff. The rest would be in a custom >Interceptor and my code. > >Please let me know if this looks like a reasonable way to make Hibernate >function in a 3-tier environment. > >Thanks, >John > >-----Original Message----- >From: Urberg, John [mailto:[EMAIL PROTECTED] >Sent: Thursday, October 16, 2003 11:21 AM >To: '[EMAIL PROTECTED]' >Subject: [Hibernate] Saving Collections from Multiple Sessions > > >We have a 3-tier Java GUI application using Hibernate as the O/R mapping >layer. We've run into the problem of dealing with updating collections from >other sessions. It seems Hibernate will recreate the collection if the >collection was loaded with a different persisted (see >SessionImpl.prepareCollectionForUpdate()). This is always the case in my >app since we send domain objects to the client and then send them back to >the server to be updated. > >I'm thinking about doing the following to work around this until I can come >up with a better idea: > >1) Add a "ignoreCollections" flag to Session with a default of false. When >set to true, it will skip the prepareCollectionsForUpdate method. >2) Classes with collections that need to be updated will implement the >Lifecycle interface and manually cascade the changes. > >Does this sound like a workable solution? > >Regards, >John Urberg > >Software is not limited by physics, like buildings are. It is limited by >imagination, by design, by organization. In short, it is limited by >properties of people, not by properties of the world. "We have met the >enemy, and he is us." - Ralph Johnson ------------------------------------------------------- This SF.net email sponsored by: Enterprise Linux Forum Conference & Expo The Event For Linux Datacenter Solutions & Strategies in The Enterprise Linux in the Boardroom; in the Front Office; & in the Server Room http://www.enterpriselinuxforum.com _______________________________________________ hibernate-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/hibernate-devel
