Optimistic Concurrency exception ALWAYS thrown when field set to "Fixed"

Question

Hello,
I'm concerned that there is a bug in the ODP.net interaction with the Entity Framework for Optimistic Concurrency Checking.
I have a sequence field called tracker_id on a table that has a before insert trigger on it, which is updated to the next logical sequence number every time the record is updated. The tracker_id attribute in the object entity has had its "Concurrency Mode" set to "Fixed".
The problem is that irrespective of whether a record has been updated in another session or not, the optimistic concurrency exception is always thrown. Please see message below:-
"Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. Refresh ObjectStateManager entries."
code below
catch (OptimisticConcurrencyException ocex)
                string message;
                if (ocex.InnerException != null)
                    message = ocex.Message + "-" + ocex.InnerException.Message;
                else
                    message = ocex.Message;
                mm.ERRORCODE = "1";
                mm.ERRORMESSAGE = "Record has been updated by another user - Full Message: " + message;
                var poobject = ocex.StateEntries[0].Entity;
                tasdb.Refresh(System.Data.Objects.RefreshMode.StoreWins, poobject);
                tasdb.SaveChanges();
            }I have tried disabling the trigger on the table, but it still does the above.
Many thanks in advance,
Graeme
Edited by: user4487499 on 09-May-2011 02:34

Answer 1

The data for the newly created row doesn't get inserted into the database until the commit is executed, so the insert trigger isn't called.
If you need to get the value without committing, then you should implement the trigger programmatically and drop the trigger from the database. The code below shows how you could do this.
ViewObject insertVO = findViewObject("myView");
Row newRow = insertVO.createRow();
SequenceImpl seq = new SequenceImpl("MY_SEQ", insertVO.getDBTransaction());
Long next = (Long)seq.getData();
newRow.setAttribute("primaryAttribute", new Number(next));
...You will need to replace MY_SEQ and primaryAttribute with the correct values for your example, but this should acheive what you want.