Resistance is futile :-) It only enforces referential integrity in that you specify the parent at entity creation time. LLAPI does NOT prevent you subsequently deleting a parent and thus orphaning the child.
The main benefit is that the 2 entities formed as a parent/child in this way form an entity group and thus may be involved in an atomic transaction. This is also the downside in that there is a persistence overhead when persisting am entity group. So it depends on your application whether you should manually maintain your own relationships using foreign keys (cheap, but no transactions) or use LLAPI (expensive but supports transactions). If you google this group for "entity group", and also the GAE documentation you will see a lot of discussion. On Thu, Oct 29, 2009 at 11:00 AM, K.Honsali <[email protected]> wrote: > > typo: desired issue => desired value > > On 29 oct, 11:58, "K.Honsali" <[email protected]> wrote: > > Salaam, > > > > Using the low-level datastore api; > > > > I have some resistance understanding the benefit of instantiating an > > Entity with a parent Key. > > Since I can just set a property , ParentId , with the desired issue. > > > > Does BigTable ensure integrity constraints if I indicate the parent > > Key using the former method? > > > > 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 -~----------~----~----~----~------~----~------~--~---
