Thanks, we have implemented the use of @Version. We have added this to a Timestamp column. It works fine for updates, however when deleting the row, a second user can update the row as it is still in his scope, the row is merged with Entity Manager and it re-inserts the row. I was hoping that this would also fail. The update fail message generated actually says row has either been updated or deleted.
Any idea how I can get this to work. Thanks. Leon Dorfling Pepkor IT email : le...@pepkoritcom tel : (021) 937 9225 fax : (021) 937 9213 cell : 083 6789 270 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Matthias Wessendorf Sent: 25-August-2009 01:36 PM To: MyFaces Discussion Subject: Re: [Trinidad] Ensure Correctness of Data. On Mon, Aug 24, 2009 at 6:07 PM, Leon Dorfling<[email protected]> wrote: > We are developing our first Java project using Trinidad. > > > > We are trying to resolve, a seemingly simple problem we have encountered, > but due to our lack of experience have not found the optimal solution. > > > > Our problem is, 2 users are viewing the same data. User1 deletes a record > from the database. The deleted record has not yet been deleted from user2's > page. Subsequentley user2 tries to update the record deleted by user1. User2 > clicks on the record (deleted by user1) and navigates to a page to update > the record. The update page is rendered with data for the row after the > deleted row in the table. > > > > How do I ensure that if user2 tries to update a deleted record, he is either > warned that the records no longer exists or the data is refreshed before he > invokes an update process. you need to implement a smarter solution here by your self. EG using unique IDs, so that one could not load a deleted object by a (wrong) ID. Another would be to implement something like optimistic locking, see here: http://api.rubyonrails.org/classes/ActiveRecord/Locking/Optimistic.html (no, there is no need to use ActiveRecord for that. Can be done with anything you are using in the back-end). But basically your application (design) has to take care of this. -Matthias > > > > Thanks. > > > > Leon Dorfling > Pepkor IT > email : le...@pepkoritcom > tel : (021) 937 9225 > fax : (021) 937 9213 > cell : 083 6789 270 > > > > Pep a division of Pepkor Retail Limited.The legal status of this > communication is governed by the terms and conditions > published at http://www.pepstores.com/cms/view/content/email_disclaimer, > which terms and conditions relate,inter alia, to confidentiality and > limitation of liability and include the names of directors and the > registration number of the company. -- Matthias Wessendorf blog: http://matthiaswessendorf.wordpress.com/ sessions: http://www.slideshare.net/mwessendorf twitter: http://twitter.com/mwessendorf Pep a division of Pepkor Retail Limited.The legal status of this communication is governed by the terms and conditions published at http://www.pepstores.com/cms/view/content/email_disclaimer, which terms and conditions relate,inter alia, to confidentiality and limitation of liability and include the names of directors and the registration number of the company.
