You would need to denormalize your data in some way to do that. The datastore does not support that type of JOIN. Do not think in terms of SQL while you are developing your data-structures.
A little bit of useful info about how the datastore works: http://code.google.com/appengine/articles/datastore/overview.html Robert On Mon, Dec 20, 2010 at 16:25, ping <[email protected]> wrote: > I have an entity A which is related to an entity B through a n:m > relationship. > > class A { > ... > @Persistent > private Set<Key> B_entities; > ... > } > > class B { > ... > @Persistent > private Group group; > > @Persistent > private Set<Key> A_entities; > ... > } > > Now i want to write a query which gives me all the entities A of a > specific group. > I can do this simply in java, but i'm wondering how this can be done > with GQL???? > > so something like this: select * from A where B.group == group > > can anyone help me out? > greets > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" 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?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Google App Engine" 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?hl=en.
