I'm pretty new to the JDO/GAE world, and I'm having some troubles
grasping the entity relationship models. I have read about entity
groups and parent keys but I can't seem to implement it correctly in
my example.
I started by trying to model my entities the same way I have done it a
million times with JPA and relational databases (see below), but it is
not working right. The first error I receive is trying to query for a
Team by a manager (select from team where manager==managerParam), I
get an error "Key of parameter value does not have a parent". So
obviously my relationships are not right. I haven't even gotten to the
Collection<Player> yet, since I can't get a simple relationship
working....
Any help would be appreciated!
@PersistenceCapable(identityType = IdentityType.APPLICATION)
public class Manager {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Key id;
@Persistent
private User user;
}
@PersistenceCapable(identityType = IdentityType.APPLICATION)
public class Team {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Key id;
@Persistent
private String name;
@Persistent
private Manager manager;
@Persistent
private Collection<Player> players;
}
@PersistenceCapable(identityType = IdentityType.APPLICATION)
public class Player {
@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Key id;
@Persistent
private String name;
}
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