Thanks Paco, that's definitely something I need to spend some more time reading up on.
For now, the approach we've taken is to simply use an unmapped property which is set on the client application which flags whether it is a new object or not then simply call session.Save(myObject) or session.SaveOrUpdate(myObject) dependant on the flag. This feels a little dirty but was very easy to implement and seems to do the job for now. I will definitely look more into the optimistic concurrency you've linked to however as it is very much of interest. Thanks for your help on this and if you (or anyone) have any other useful resources i'd be very interested. Cheers, Dan 2009/4/1 Paco Wensveen <[email protected]> > You can read about it in the docs here: > > http://www.hibernate.org/hib_docs/nhibernate/1.2/reference/en/html/mapping.html#mapping-declaration-version > and here: > > http://www.hibernate.org/hib_docs/nhibernate/1.2/reference/en/html/transactions.html#transactions-optimistic > There might be other solutions for your problem, or you might not want to > do this, but a nice side effect of optimistic concurrency with versioning is > that nhibernate can distinct saved and unsaved entities by the version > number. > On Wed, Apr 1, 2009 at 2:33 PM, DannyT <[email protected]> wrote: > >> Thanks for that, I've just been looking at this in the docs, could you >> clarify that this means I need to add a version column to my table and a >> Version property to my entity? >> >> 2009/4/1 Paco Wensveen <[email protected]> >> >>> You can use a "version" int property if you also want optimistic >>> concurrency >>> >>> >>> On 4/1/09, DannyT <[email protected]> wrote: >>>> >>>> We're using GUIDs as our identifier, however our entities may be created >>>> on the server (which we rely on NH to sort out the IDs for) or within a >>>> client application which will generate and assign the ID. >>>> >>>> Currently when trying to save an entity generated from the client app >>>> which will have a GUID but will not already exist in the NH db I get the >>>> error: >>>> >>>> NHibernate.StaleStateException: Unexpected row count: 0; expected: 1 >>>> >>>> Should NH not detect the entity doesn't already exist in the database, >>>> despite the fact it has an ID and insert it? Otherwise what else should we >>>> be doing to allow for this? >>>> >>>> Dan >>>> >>>> >>>> >>> >>> >>> >> >> >> -- >> http://danny-t.co.uk >> >> >> >> -- http://danny-t.co.uk --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "nhusers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/nhusers?hl=en -~----------~----~----~----~------~----~------~--~---
