Jorge, thank you. I read that section but it didn't sink in. I guess I have to re-read the docs again.
On Oct 27, 3:26 pm, Jorge <athenas...@gmail.com> wrote: > You may want to take a look to the Object Fields and Entity > Properties section at the bottom of the Defining Data Classes > document > herehttp://code.google.com/appengine/docs/java/datastore/dataclasses.html > > Jorge Gonzalez > > On Oct 26, 9:33 am,SweetHotDaddy<thomas.si...@gmail.com> wrote: > > > Suppose I have class A with fields > > > @Persistent > > int id > > > @Persistent > > String name > > > @Persistent > > int age > > > This class gets deployed (Version 1) to App Engine and data gets > > persisted to the datastore. > > > I then modify class A by adding a new field. > > > @Persistent > > address. > > > and then deployed the new version (Version 2) to App Engine and data > > gets persisted to the datastore. > > > Finally I modified class A again by removing the age field and I again > > deployed the new version (Version 3) to App Engine. > > > Summary, the initial deployment, Version 1, had Class A. The second > > deployment, Version 2, I added a new field, address. The third > > deployment, Version 3, I deleted the 'age' field. > > > In a typical database, when I add a new column, it typically defaults > > to null or 0 and when I delete a column, the data gets deleted. Then I > > update my SQL statements to take into account the deleted and new > > columns. > > > My Question ... When I try to query the datastore in the third > > deployment, will I be able to get back the data which was stored in > > the first and second deployments? Does DataNucleus know that fields > > were adding/deleted? What happens to those orphaned fields, for > > example Version 3 of my app got rid of the 'age' field but I'm > > assuming that data is still in the datastore? --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~----------~----~----~----~------~----~------~--~---
