Hello, I've recently been tackling almost the same thing. I'm using Google App Engine and app-engine-patch so I can't help you on the best method for implementing the optimistic locking at the database level to avoid race conditions (though I'm even more lost as to how to achieve the same thing using the datastore)
What has me stumped is what the best method is for hiding the field containing the timestamp. I'm manually setting the widget for the field on the form in the admin system to be a HiddenField but it still displays the label and surrounding divs. I've come up with a workaround but it is pretty ugly. Am I doing something dumb? Andy 2009/4/29 PierreR <p.radermec...@gmail.com> > > Hello, > > I have been searching the group on the subject but have not managed to > pull a satisfactory solution out of it. > > How is the recommended way to implement optimistic locking in the > django admin ? > > Let's say I have a version field or timestamp sent to the user-agent > together with the record (the classic solution). I need to compare the > value with the database version of it. I probably need to read the db > value with a "select for update" or to use "update where > timestamp=:timestamp" to avoid a race condition between the version > check and the update. > > A warning message to the user should be sent if the record has been > concurrently updated (with the data previouly sent). Where do I code > the following ? (I am not planning to implement any merging > functionnaly) > > I have started with a pre_save signal but it is probably not the best > way to "decorate" the save process (is it ?). I probably want to > change the save() into an "update where" or at least cancel it. > > Is it safer/useful to use > django.middleware.transaction.TransactionMiddleware together with Form > in that context ? Where are the hooks ? > > In short how to I plumb this together ? > > Thanks so much for your advices. > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
