I am trying to save and retrieve data in google app engine in
hierarchical manner.
1.
In such a case ,where I am using key's for reference to another entity
(i.e parent --> child)
@PersistenceCapable(identityType = IdentityType.APPLICATION,
detachable = "true") public class Item {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Key key;
@Persistent
private List<Key> childs;
//
}
there is no replication of data.
Is it possible that child entities get saved automatically when parent
is saved in above case where I am using Keys ?
2.
If I tried same without keys ..
@PersistenceCapable(identityType = IdentityType.APPLICATION,
detachable = "true") public class Item {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Key key;
@Persistent
private List<Child> childs;
//
}
In this case when I saved parent entity then child's also get saved
automatically . But then there is replication of data i.e for
different child's of same parent there are separate copies of
parent's.
Can anybody give me some Ideas and Links ??
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