Java Google应用程序引擎JDO关系

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;
}
     }

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我有两个问题，我答对了吗？
1）（用户和一般数据之间的模式）
2）（将实例添加到google数据存储）

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            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();
    }

            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();
    }