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?
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