anyone have a recomendation on the best way to store millions of child objects in data nuclues and maintain their relationship to a single persistant parent?
On Oct 8, 10:21 am, Benjamin <[email protected]> wrote: > sorry for the dup post > > I'm trying to find guidence on managing one to many releationships in > the data store when the number of children the parent will have will > be huge - 32000 children added to a parent a day > > a simple parent class: > > @PersistenceCapable(identityType = IdentityType.APPLICATION, > detachable = "false") > public class Parent { > > �...@persistent(mappedBy = "parent") > private ArrayList<Child> points; > > a simple child class > > public class Child { > @Persistent > private Parent parent; > > and the parent arraylist is getting many children added to it and the > datastore updated. I'm afraid that whenever i query for the parent > object i'm going to get all of the children which i would never need > to do - i would want to get parts of the children collection and i do > want to maintain the relationship so parent deletes are cascaded. > > How do you query the datastore and get a parent without the children - > it looks like the child collection gets populated by default when you > just do a query like this: > > Query q = pm.newQuery(Parent.class, "key== k"); > k.declareParameters("Long u"); > List<Parent> result; > result = (List<Parent>) q.execute(key); > > with a huge number of children, wouldn't this query be very slow? --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
