Google App Engine JDO关系

Question

架构：1个用户有1个GeneralData，没有用户

，GeneralData不能存在

@PersistenceCapable
public class User implements Serializable{

private static final long serialVersionUID = 1L;

@PrimaryKey
@Persistent
    private String key;

@Persistent(defaultFetchGroup = "true")
@Element(dependent = "true")
private GeneralData data;

public void setKey(String key) {
    this.key = key;
}

public String getKey() {
    return key;
}

public void setData(GeneralData data) {
    this.data = data;
}

public GeneralData getData() {
    return data;
}
     }

---

    @PersistenceCapable
    public class GeneralData implements Serializable{
private static final long serialVersionUID = 1L;



@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
    private Long key;

@Persistent
private String name;

@Persistent(mappedBy = "data")
    private User user;

public void setName(String name) {
    this.name = name;
}

public String getName() {
    return name;
}

public void setKey(Long key) {
    this.key = key;
}

public Long getKey() {
    return key;
}


public void setUser(User user) {
    this.user = user;
}


public User getUser() {
    return user;
}

      }

我有2个问题，我做得对吗？       
1）（用户和GeneralData之间的模式）       
2）（添加实例到谷歌数据存储）             

<小时/>

            PersistenceManager pm = PMF.get().getPersistenceManager();      
    User onUser = new User();
    GeneralData gd = new GeneralData();
    gd.setName(usrname);
    onUser.setKey(usrname);
    onUser.setData(gd);

    try {
        pm.makePersistent(onUser);
    } finally {
        pm.close();
    }