Hi, I think the following links useful.
http://groups.google.com/group/google-appengine-java/browse_thread/thread/d13d469752c825e7 http://groups.google.com/group/google-appengine-java/browse_thread/thread/79a53aba561effc8 Hope this helps, thanks. 2010/3/26 Zac Witte <[email protected]>: > I have a persistent class called Location, which already exists in the > datastore and I'm trying to add a new variable called numCheckins. Is > this possible without wiping out all the existing objects? My attempts > so far have resulted in the following error whenever I try to retrieve > one of the existing objects: > > WARNING: Error getting location from hash. Datastore entity with kind > Location and key Location(1) has a null property named numCheckins. > This property is mapped to is.loc.dataobjects.Location.numCheckins, > which cannot accept null values. > > I tried giving it a default value in the definition (ie. int > numCheckins = 0;) which had no effect. > > I tried adding the nullValue = NullValue.DEFAULT property to the > @Persistent annotation, but I get a message saying default values not > supported > > I'm still new to GAE - what is the correct way of handling this? > > Thanks! > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine for Java" 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/google-appengine-java?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Google App Engine for Java" 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/google-appengine-java?hl=en.
