On Saturday, May 26, 2012 4:45:32 AM UTC+2, Anthony wrote: > Yes, I guess to be more clear, it should indicate that on updates, it > tries to compute the value using the fields being updated. If one of the > fields required to compute the value is not included in the update, then > the compute won't be updated. Note, the compute should happen as long as it > doesn't require any fields that are not being updated. So, this should only > be a problem if the compute requires multiple fields, and some of them are > being updated and some are not. To accommodate that case, though, the DAL > would have to retrieve the existing record from the db in order to get the > current values of the fields that aren't being updated. Of course, you > could always do that explicitly in your code and then include those fields > in the update as well. > > Anthony > > So if the computation needs two fields and only one is updated, it won't execute on update. It makes sense when I rethink the logic, but I wouldn't have thought of this right away. I recommend mentioning this explicitly in the book.
I see this as one of those little things that can cause a lot of troubleshooting and then a grumbling facepalm, an hour or two later :)
